“Uh-oh,” Sammy said.

  “No kidding,” I agreed.

  There was something in my bag that absolutely-positively-for-sure-without-a-doubt should not have been in there.

  “You brought another Fizzy to school!” I said. “How could you?”

  A tiny little Fizzy had walked out from behind my calculator. He was the size of a cockroach and looked like one too, only he stood upright on three legs. He was purple, he was furry, and he was trouble.

  “Of all the Fizzies you could have brought to school, you brought him?” I asked.

  Floyd opened his mouth to say something but stopped, scratching his head like he was still trying to determine how to get out of trouble.

  “What do you have to say for yourself?” I asked in my best Miss Yoobler voice.

  Sammy thought I was talking to her. “The acoustics in here are really good,” she said. She practically had her whole head inside my backpack. Actually, so did I. It’s a big backpack. Also stretchy.

  Sammy was right: The sound inside my backpack was surprisingly awesome. It was like a concert hall.

  “You know Floyd’s travel buddy?” Sammy asked. She turned in my direction and her nose got squashed against the side of my head.

  “Sammy, meet Grabstack,” I said.

  Grabstack was a total blowhard who thought he was a theater director. He was always putting on plays in Fizzopolis, usually of the Shakespeare variety. Grabstack was incredibly demanding with his actors. Somehow he’d acquired a British accent, probably from watching soap operas Dr. Fuzzwonker wired in from London.

  “Why are people in my theater?” Grabstack said in his squeaky little British voice. “We’re not even in previews yet! Get them out of here!”

  Floyd looked up at me bashfully. “We’re in rehearsals. It’s a closed set.”

  “This is outrageous,” I complained. “Who else have you got in there?”

  Grabstack turned his nose up at Sammy and me. “They don’t appreciate the theater. They’re barbarians.”

  Floyd whispered something to Grabstack that made him roll his eyes.

  “Oh, all right,” Grabstack agreed. “If it will clear the theater, I’ll introduce the cast.”

  Grabstack pushed my calculator so it lay flat on the bottom of my bag and one by one he introduced everyone who was sitting on it.

  “We are bringing an enthralling adventure to life,” Grabstack said. “It’s my first original production, starring Mr. Pencil.”

  “Hey, that’s my pencil,” I said. Mr. Pencil rolled forward.

  “And here we have Dime and Penny,” Grabstack continued. “Also Miss Ball of Rubber Bands, and the evil Mr. Lint Ball.”

  The dime and the penny and the rubber band ball and the lint just sat there.

  “And the star of our show, the Floozemeister!” Grabstack yelled at the top of his lungs. He held out a wad of Snood’s Flooze, the yuckiest candy in the world. It was made at the Snood Candy Factory by Garvin Snood’s dad. The glob of Flooze had two eyes that were made of pebbles. It looked like a tiny bald head.

  “I love this play,” Sammy said. “They can really act.”

  “At last! Someone with real taste around here,” Grabstack said. “She can stay.”

  Floyd held out his hand. “This is Wrinkles, who used to be a grape,” he said.

  “Floyd, that’s a raisin,” I explained. “And this play involving all the junk in my backpack cannot go on. At least not while we’re at school.”

  “Off with his head!” Grabstack yelled.

  “Wow, he really is a feisty little Fizzy,” Sammy said.

  “You have no idea,” I said.

  “He puts on weird plays in Fizzopolis all the time. What an egomaniac.”

  “If you’re going to insult me, please take your heads somewhere else,” Grabstack said. “We have important work to do.”

  I looked at my best good buddy and I could tell he was in over his head. I felt sorry for Floyd, so I offered him a deal.

  “You guys can practice in here all you want, but when we go to school you can’t bring Grabstack with you. It’s too dangerous.”

  Floyd and Grabstack had an epic Fizzy argument, so I pulled my head out of the backpack to get some fresh air.

  “This might take a while,” Sammy said as she stood up.

  When we both turned around, a crowd had gathered. There were several Fizzies taking their lunch break.

  “I think they’re waiting for the show to start,” Sammy said. All the Fizzies nodded while they ate their sandwiches. There were green Fizzies and blue Fizzies and one covered in stripes.

  We waited as Floyd and Grabstack argued. And argued. And argued.

  Finally, after about a million years, Grabstack popped out of the bag and stood holding the Floozemeister in one three-fingered hand.

  “If I can’t lead this play at the Floyd Theater, no one can!” he blathered.

  “It’s not a theater,” I said. “It’s my backpack!”

  Grabstack turned in the direction of the Fizzomatic machine and threw the glob of Flooze as hard as he could. The Floozemeister flew across the great expanse of Fizzopolis, bounced three times, and landed on the ground next to one of the giant Fizzomatic tubes.

  “I shall take my talents elsewhere, thank you very much,” Grabstack said.

  Grabstack walked away on his three legs. The crowd of Fizzies cheered loudly, and their fur fizzed and popped, so Grabstack stopped and took a bow before disappearing into Fizzopolis.

  “Well, I guess that’s that,” I said. “No more trouble like we had today at school.”

  “I feel sort of bad for Floyd,” Sammy said. “I bet he liked having a travel buddy.”

  But Sammy was wrong about that, because a few seconds later Floyd jumped onto my shoulder and mumbled into my ear.

  “Floyd says this was all Grabstack’s idea. Apparently he snuck into my backpack and talked Floyd into putting on the play. It was really cutting into his nap time.”

  Floyd sat contentedly on my shoulder with the evil Mr. Lint Ball in one hand and Wrinkles in the other, pretending they were characters.

  “See, you can have plenty of fun with the stuff in my backpack without Grabstack bossing you around.”

  Floyd nodded happily.

  “Hang on,” Sammy said. “I’ll get Dime and Penny!”

  The three of us put on a play while the Fizzies watched. Boy, was that fun. The evil Mr. Lint Ball was banished to the Fizzy forest in the end and all the Fizzies in Fizzopolis fizzed and popped and cheered.

  We decided there was no reason to find my dad and went to work doing the normal chores we had in Fizzopolis. But while we were busy watching the Fizzy babies in the Fizzopolis nursery and helping Franny clean the lagoon, someone else was causing trouble.

  Grabstack was planning something that could mean big trouble in Fizzopolis!

  The next morning was my favorite day of the week: Saturday. I could sleep in and when I got up there were old monster movies on television. They played them on the Pflugerville public access station, and Floyd loved watching giant lizards beat up big monkeys.

  “Come on, my best good buddy. It’s Saturday!” I said.

  Floyd slept on a pillow next to me. When he heard the word “Saturday” he totally flipped out. He was all the way down the hallway and into the kitchen before I set one foot on the floor. We always go to the kitchen first on Saturday mornings so we can make gigantic bowls of cereal.

  “Hang on, Ima comin’!” I yelled. Then I did eleven cartwheels on my way to the kitchen. Floyd was already waiting with two bowls, the big kind we use to make cookie dough. I grabbed about ten cereal boxes and we poured a little bit from each one until both bowls were overflowing with graveyard mixes of awesome.

  “Milk time!” I said, and I opened the refrigerator door, where we usually kept a couple of gallons on hand.

  I was just about to reach in and grab both gallons when I saw something unusual.

  “Hey, look! It’s m
y long-lost fart putty!”

  Sitting right there on top of a block of cheddar cheese was a glob of goopy green stuff. Floyd jumped onto my shoulder and peered into the fridge with me.

  “That’s super-duper strangomatic,” he said.

  “I know, right? What’s my fart putty doing in the refrigerator?”

  But Floyd didn’t think it was my missing gag toy. Whatever it was made him nervous.

  “What’s wrong?”

  Floyd mumbled some words I couldn’t understand, and then he said, “Better show it to Dr. Fuzzwonker. I don’t think that’s fart putty.”

  I moved in closer and put my face right up next to the cheddar cheese block. It was cold in there. Upon closer inspection, I started to think maybe Floyd was right. Whatever that gloppy green goop was, it didn’t look exactly like my missing stuff.

  I could feel a busy day coming on, so I suggested we eat a ton of cereal before finding my dad, and Floyd agreed. We were both hungry as bears, so we plowed through two gargantuan bowls of cereal in three minutes flat. After that I let Floyd brush my teeth and comb my hair (he enjoyed this routine more than I did). Then we set off for my dad’s laboratory. We took the green-globbed block of cheddar cheese with us.

  “Maybe it’s mold,” I said as we traveled down the elevator.

  “Maybe it came out of my nose,” Floyd said as we walked across Fizzopolis.

  “I wonder what it tastes like,” Floyd asked when we arrived at the tree that held Dr. Fuzzwonker’s lab. We both looked up and saw my dad’s lab teetering back and forth in the highest branches and wondered for the millionth time why he put his place of work up in a tree.

  There was a rope hanging all the way down to the ground, and I pulled on it like I was ringing a giant bell. A doorbell sound rang way up above us, and I saw my dad’s head pop out of a window in the tree house.

  “Hello down there!” Dr. Fuzzwonker yelled. His voice was far away like someone calling from across an ocean. “Are you sure he won’t break anything?”

  Dr. Fuzzwonker didn’t usually let Floyd into the laboratory.

  “We have something to show you. Come down here?” I asked.

  Dr. Fuzzwonker’s head disappeared into his lab, probably to calculate the pros and cons of having us come up or him come down. This usually took about nine seconds and—

  “Climb aboard!”

  Okay, seven seconds.

  By “climb aboard” my dad meant hold on to the rope, which I did. It was tougher than usual because I was holding the block of cheddar cheese in one hand.

  My dad had the rope attached to a wheel in his laboratory so he could roll it up like a garden hose. And off we went, up into the air where we could see the whole world of Fizzopolis.

  It always surprised me how big it was. There were so many Fizzies working in every corner, I couldn’t count them all. The conveyor belts rolled up and down and left and right, carrying countless bottles of Fuzzwonker Fizz. It was a factory and a habitat all at once, teeming with colors and bustling with activity.

  “I guess this is why he likes it up here,” I said. “So he can keep an eye on everything.”

  “And drop water balloons,” Floyd said.

  Entering the laboratory meant walking across a rope bridge from the drop-off point and climbing a ladder, then sliding down a tube. We walked, climbed, and slid and then we were standing next to my dad.

  “It’s a lot of work getting up here,” I said. “Maybe you should install an elevator.”

  “Interesting idea,” Dr. Fuzzwonker said. “I’ll run the math and take it under consideration.”

  I looked around the laboratory and saw four experiments going at once, but I’d only ever seen samples of one.

  “Hey, the furry candy is getting more flavors,” I said.

  I shouldn’t have said that because Floyd loves sampling new fizzy candy. He dove off my shoulder with an arc that looked like a basketball heading into a hoop. Just before Floyd landed, Dr. Fuzzwonker grabbed a butterfly net and held it over his experiment. Floyd landed in the net and started flopping around like a fish.

  “We just ate a gallon of cereal,” I said. “How can you be hungry?”

  “If you don’t mind, I’ll put Floyd in the time-out tube while you’re visiting,” Dr. Fuzzwonker said.

  “Good idea,” I agreed, and Dr. Fuzzwonker turned the net over into a big glass container. Floyd bounced back and forth like a Ping-Pong ball until he tired himself out, and then he smashed his face up against the glass and watched us. He also fogged up the glass and started drawing messages with his finger like I’m bored and I can’t breathe and not fair!

  “We better make this fast,” Dr. Fuzzwonker said. But I was so curious about the experiments that I waited to mention the block of cheddar cheese in my hand.

  “Furry candy is looking good. Can I try one?” I asked.

  Dr. Fuzzwonker took a pair of gorilla-sized tweezers out of his white lab coat and picked up an orange block about the size of a Lego. He held it right up next to my eyeball so I could get a good look at it. The fur was really thick, like shag carpet.

  “Are you sure this thing is safe to ea—”

  I didn’t have time to finish asking whether or not I should put that thing in my mouth before Dr. Fuzzwonker jammed it in there. At first it felt like I had a hair ball on my tongue, but then it started to disintegrate like cotton candy. There was some kind of far-out fizzy filling on the inside that tasted like oranges and chocolate mixed together.

  “Wow, that was fantastic!” I laughed.

  Dr. Fuzzwonker held up a mirror, and I saw that my teeth looked like they’d just gotten a serious spray tan.

  “What the!” I said.

  “It still needs some refining,” Dr. Fuzzwonker said. “Be happy you didn’t try the black one.”

  “How long are my teeth going to be orange?” I was thinking about not smiling all day at school on Monday.

  I looked over at the time-out tube and Floyd had written a message in the fog on the glass. Harold = dumb.

  “Don’t worry,” my dad said. “It will come off if you eat a banana.”

  My dad handed me a slice of banana on a toothpick and we moved to the next experiment. Over at the time-out tube, the fog read: Floyd wants banana!

  “What’s this one?” I asked as we came across a bunch of beakers full of colorful balls.

  “Exploding Jelly Beans,” Dr. Fuzzwonker said. “But I wouldn’t try one. They’re harmless, but they have some problems.”

  My dad picked up a purple one and popped it in his mouth. It exploded and smoke started pouring out of his nose.

  “It’s an explosion of flavor, so that part is working,” Dr. Fuzzwonker said. “But the smoke tastes like motor oil. Superb start, yucky finish.”

  We walked by another station that had something called Regenerating Ropes. They were licorice vines that grew back after you took a bite. “Very unstable,” was all my dad said about those.

  “I’ll give one of these to Floyd,” Dr. Fuzzwonker said as he picked up something he called a Fabulayerous. It was chocolate on the outside, and it was the size of a baseball. He opened the hatch on the time-out tube and dropped it in, and we both watched Floyd go to work.

  “There are seven hundred layers in a Fabulayerous, all with different flavors. And there’s ice cream in the middle.”

  “No way!” I said.

  Floyd was through the first layer, but he had six hundred and ninety-nine to go.

  That Fabulayerous was going to keep Floyd busy for quite a while, so it was the perfect time to tell my dad about the weird stuff we’d found in the refrigerator.

  “What’s that you’ve got there?” Dr. Fuzzwonker asked me.

  He was pointing at the block of cheddar cheese.

  “This is why I came up here,” I said. “See this green stuff?”

  Dr. Fuzzwonker put his face right next to the cheese and used his tongs to latch on to the gloppy green stuff.

  “Cu
rious,” he said.

  “I thought it was my fart putty, but Floyd wasn’t so sure.”

  Dr. Fuzzwonker moved the specimen under a microscope and started dialing it in.

  “Cheese!” he yelled.

  “Really? That’s weird.”

  “No, I mean I’m hungry. Slice me off some of that cheddar, will you?”

  I used a butter knife I found lying next to the Fabulayerous samples and lopped off a piece of cheese. I handed it to my dad and he munched on it while he worked.

  “Oh my,” he said.

  “What? What is it?” I asked.

  “It’s definitely not fart putty,” he said. “It’s something far more dangerous.”

  Fart putty is pretty dangerous stuff, so this was turning into a big deal. I looked over at Floyd, but he was busy making his way through layer number one hundred and twelve of that crazy Fabulayerous.

  “Take a look,” Dr. Fuzzwonker said. “But be warned: It’s terribly disturbing.”

  I wasn’t sure I wanted to see what gloppy green stuff looked like magnified a million times. Come to think of it, I didn’t want to see what fart putty looked like magnified that much either. Who knows what kind of gross is in there. Curiosity won me over though, and I leaned next to the microscope.

  “Dad, this is bizarro to the max.”

  My dad didn’t respond and when I looked up he was cutting off another piece of cheese.

  “It’s . . . it’s . . . ,” I said. “It’s moving!”

  “I know,” Dr. Fuzzwonker said as he ate more cheese. “Fascinating, don’t you think?”

  Whatever was under the microscope looked like the inside of a lava lamp.

  “We better take a gander at the security footage,” Dr. Fuzzwonker said.

  “We have security footage?” I asked.

  “Why, sure we do. Follow me.”

  There was a British soap opera playing in the corner of the lab on a television. I didn’t notice until I got closer, but Grabstack was sitting in a miniature recliner watching the show. He was holding a thimble full of popcorn.