French Narrator: Ah, Sandy Cheeks is going out of town and has asked SpongeBob and Patrick to do a little pet-sitting for her. [inside the dome are a few animals in cages and/or jars]

Patrick: Pet-sitting? Won't that hurt them? [SpongeBob and Patrick walk up to a bird cage]

French Narrator: Perhaps she should have asked someone else. [Patrick whistles at the bird]

SpongeBob: Gee, Patrick, I didn't know you spoke bird.

Patrick: No, that's Italian, SpongeBob. [Sandy puts a big sack down]

Sandy: Okay boys, this here is Birdy's food. Feed him twice a day.

SpongeBob: This whole sack?

Sandy: No, just a cup's worth. [all walk over to a cricket] This here's my cricket. [the cricket makes noises] He's saying hello to you. Ain't he cute?

SpongeBob: Uh, sorry, I don't speak Italian.

Sandy: And this here's Snakey. [holds up the snake that has a mouse in its belly]

SpongeBob: What's that lump in its belly?

Sandy: Well, that's his dinner. [SpongeBob pokes it and the mouse chuckles] Well, I guess that's it. I gotta go. [walks off with a suitcase] See you guys in a couple of days.

SpongeBob and Patrick: Bye, Sandy! [notices the worm in a jar]

SpongeBob: [gasps] Wait! You forgot about this pet!

Sandy: Oh, that's only Wormy. He don't eat much. [walks out]

SpongeBob: Look at him, Patrick, isn't he great? Hey, little fella.

Patrick: Kitchie-kitchie koo, koo.

SpongeBob: Aw, look, isn't he just precious? Let's take him out to play. [cut to SpongeBob playing hide-n-seek and counting] 998, 999, 1,000. Ready or not, here I come! [turns around and takes the table cover off of Patrick's head]

Patrick: You found me. [both look for Wormy, who is on a leaf]

SpongeBob and Patrick: There you are! [cuts to SpongeBob and Patrick hiding behind a tree. Wormy pops up behind it] He found us! [they laugh]

[A montage begins over the song "That's What Friends Do." In the montage, the boys throw flowers near Wormy while circling around him. They then run around the treedome with Wormy on their helmets. SpongeBob and Patrick then raise their arms in delight then plunge down on the grass. Amid previous shots of our dynamic duo enjoying their time with Wormy, the pair hold hands and spin round in circles with Wormy on a plant, smack dab in the center of the boys. The montage ends with SpongeBob and Patrick's heads circling Wormy over a heart background. Fade to the pair lying on the grass]

Patrick: Gee, SpongeBob, I don't want today to end ever.

SpongeBob: I know, Patrick, days like today only come once, maybe twice in a lifetime. Savor every moment. And it's all thanks to Wormy. I made this for Wormy. [puts a 'Best Friend' ribbon on Wormy] Our new best friend. [puts Wormy back in his jar] Until tomorrow, new best friend. Don't be sad, little buddy. We'll be back first thing in the morning for frolic and fun.

Patrick: Why must the sun set on this perfect day? Sleep well, Wormy. [cries as they both walk home]

SpongeBob: Aw, don't be sad, Patrick. It's only until tomorrow.

[cut to the Bikini Atoll island as day turns into night. Meanwhile, back at Sandy's treedome, a now live-action Wormy sheds his skin one last time, turns himself into a chrysalis, then emerges from said chrysalis, now as a butterfly. The next morning, the rooster crows and SpongeBob wakes up.]

SpongeBob: Here I come, Wormy! [Patrick pokes his head out of SpongeBob's alarm clock]

Patrick: Me, too! [both run off to Sandy's with their water helmets already on] And then we're gonna play tag, and then we're gonna color, and then we're gonna build a house of cards!

SpongeBob and Patrick: We're back, Wormy! Wormy, Wormy? [holds up the jar with Wormy in it, who is now a butterfly]

Patrick: Wormy? Where's Wormy? What's that thing?

SpongeBob: He's gotta be in here. [opens up the jar, causing Wormy to fly out] I think something bad happened to Wormy. [the best friend ribbon and Wormy's chrysalis are shown inside the jar]

Patrick: He left his "Best Friend" ribbon behind!

[The butterfly flies onto SpongeBob's helmet. Cue a live-action close-up of a buzzing horsefly's face. SpongeBob and Patrick scream and run behind Sandy's table.]

Patrick: What is that thing? [the butterfly is on the tree]

SpongeBob: I don't know, Patrick. But whatever it is...it must've eaten Wormy!

Patrick: [in tears] Why does this keep happening to me?!

SpongeBob: Quick, Patrick! We've gotta make a run for the door! [they start to run to the exit but the butterfly flies in front of the door] No! Patrick, it’s blocking our only exit! [they begin to run backwards to the back of Sandy's tree]

Patrick: Now what? We're trapped in here with that... that... "Best Friend Eater!"

SpongeBob: Let's not panic. We just have to stick together. Remember, it's two against one. Right, Patrick? Patrick? [sees Patrick gone and the butterfly flying at him and shrieks] It’s eaten Patrick! [runs away and jumps in a barrel and sees Patrick in it] Patrick, you're alive!

Patrick: I am?

SpongeBob: Patrick, we can't leave this horrible monster in Sandy's house. It might eat Sandy's other pets!

Patrick: Or worse, it might eat Sandy's pets.

SpongeBob: No, it might eat Sandy! We've gotta get it out of here!

[Bubble transition to SpongeBob and Patrick now hiding behind Sandy's table and Sandy's phone in a jar to trap the butterfly and the phone begins to ring.]

Patrick: It's for you! [the butterfly named Wormy begins to fly by the jar]

SpongeBob: It's working. It’s gonna answer it. [But instead the butterfly just flies past the jar and the lid closes]

Patrick: Tartar sauce.

[Bubble transition to Patrick on a plate with an apple in his mouth.]

SpongeBob: You look pretty appetizing, Patrick. Now, just stay here and wait for the monster. I'll go get the net. [walks off and the butterfly begins to fly by and land on Patrick's butt which makes Patrick feel scared]

Patrick: [whimpering, spitting out the apple] SpongeBob! Hurry up with that net!

SpongeBob: Hold on, Patrick! [searches through Sandy's trunk for the net]

Patrick: I really don't taste that good, Monster. [Wormy crawls down Patrick's helmet. Patrick sees the buzzing horsefly close-up and runs off screaming. SpongeBob runs by with the net]

SpongeBob: I'm coming, Patrick! [Patrick then rips right through the net and crashes into the tree, causing some acorns to fall into his helmet. SpongeBob sees his broken net as Wormy corners him] No, Monster, please don't eat me! No, no, no! Spare me, I don't taste good, no! Please! Wait a second. [takes out a bottle of bubbles and blows one to get Wormy stuck in one. SpongeBob jumps with glee suddenly wearing a cheerleader outfit with pom-poms] Yeah! [Wormy flies out of the treedome, still in the bubble. Patrick shuts the door behind Wormy] We did it, Patrick! Sandy's gonna be so proud of us. We got that horrible monster out of her house and best of all her pets are safe. 'Cause that horrible creature is now... [Wormy flies to the Krusty Krab] ...heading straight for the Krusty Krab! [both run off] It's going in the front! Let's use the secret entrance. [both go inside a door that's in a rock and then appear inside the Krusty Krab coming out of another rock. They gasp as Wormy flies toward Squidward and Mr. Krabs, who are taking pictures]

Squidward: Okay, hold still.

Patrick: It's gonna eat Squidward and Mr. Krabs! [both jump at them]

SpongeBob: Hit the deck, Mr. Krabs!

Squidward: Say "money."

Mr. Krabs: "Money!" [Squidward takes the picture. It reveals SpongeBob and Patrick jumping on top of Mr. Krabs]

Mr. Krabs: What's the meaning of this, SpongeBob?!

SpongeBob: We're in serious danger. There's a-a-a...a monster out there.

Mr. Krabs: Is it a paying customer?

SpongeBob: Oh no, Mr. Krabs. It doesn't want to eat Krabby Patties. It wants to eat you!

Patrick: [crying] Just like it ate Wormy!

Squidward: Um, Wormy? [SpongeBob and Patrick cry]

SpongeBob: Why? Why? He was so young.

Patrick: We'll never forget you, Wormy.

Squidward: Well, if Moron Theater's over, I think I'll just take a look at this "monster." [SpongeBob, Squidward, Patrick, and Mr. Krabs pop their heads up from the register boat to take a look. Wormy is fluttering around in a bubble] That's the monster?

Patrick: Pretty scary, huh?

SpongeBob: A living nightmare!

Squidward: I should have known. [gets up and steps out of the boat and begins to walk away] Well, that's it. I'm getting off the Looney Express.

Mr. Krabs: Now just 'cause you swabs never seen a creature like this doesn't mean it's dangerous.

SpongeBob: We tried to warn them. I can't watch! [pushes his eyes into his head]

Squidward: Get a load of the scary monster. [laughs] Monster.

Mr. Krabs: Aww, it looks harmless...

Squidward: It's kinda cute.

Mr. Krabs: It reminds me of money!

Squidward: Monster. [both laugh until they see the horsefly up-close and personal. Squidward and Mr. Krabs scream as their teeth and eyes fall out and they both run away]

SpongeBob: Squidward?

Patrick: Mr. Krabs? [SpongeBob screams when he sees their underwear and hat only]

SpongeBob: [screams] It ate them! And there it goes! [Wormy flies out of the Krusty Krab] First Wormy, then Squidward, Mr. Krabs! [has three finger puppets for each person] That flying monster has eaten three friends too many. We must inform the citizens! Evil has surfaced. The fate of Bikini Bottom is in our hands, Patrick. Now let's roll.

Patrick: Aye-aye, captain. [pushes a lever to make the boat sail out of the Krusty Krab. Cut to SpongeBob and Patrick on the streets]

SpongeBob: Okay, Patrick, this is a very delicate situation. It must be treated with great care and sensitivity.

Patrick: Gotcha.

SpongeBob: Run, everybody, run!

Patrick: Hey! Monster on the loose!

SpongeBob: Monster! [everyone runs away screaming. SpongeBob and Patrick give each other a thumbs up. Cut to SpongeBob and Patrick putting up a sign of the butterfly saying "Beware" when a crowd of citizens runs by screaming. Wormy flies by and SpongeBob and Patrick hide in the bucket of glue and bounce off. Cut to SpongeBob inflating a balloon but then inhales the air in the balloon so he can float in the sky.]

Patrick: [using a megaphone] Attention, Bikini Bottom! There's a flying monster that's going to eat you!

[everyone gasped and screams, and runs away. Cut to SpongeBob waving his arms and horrifyingly pointing at Wormy flying by. Everybody runs off, and in the commotion, a lamppost gets knocked over and the whole city is set on fire.]

Realistic Fish Head: Attention, attention! This just in! [a TV shows a real monarch butterfly] A giant monster is attacking Bikini Bottom. [a man watching the announcement swallows his eyes and has them appear in his mouth when he screams and runs through the wall]

SpongeBob: We did it, Patrick! We saved the city! [in the background, a meteor flies down and destroys a building and it burn down with black smoke] Just think what might of happened if we didn't tell everyone about the monster.

Patrick: About the what? [just then, Wormy flies by. SpongeBob, Patrick, and everyone else run away from Wormy, but Wormy always finds them no matter where they go. Eventually, the crowd stops at a traffic light to allow another crowd through. The first crowd passes as well, and soon enough, Wormy stops at the light, too. The crowd runs inside of a burnt building, and Wormy enters as well. In the struggle to get out, all of the citizens are ejected through the chimney. Cut to the crowd running. As SpongeBob screams, his mouth engulfs the camera. Bikini Bottom's welcome sign is burnt snaps in half with black smoke, and a "Beware" poster drifts through the wind. Then, a bus drops off Sandy. Sandy sees the destroyed town of black smoke]

Sandy: Shoot! Looks like a twister hit this place. Where is everybody? [During the downtown burned down as Wormy flies by] Oh, hey there, Wormy. [puts him in a jar] You weren't supposed to change till I got back. That oughta hold ya, little guy. [everyone runs up to Sandy, SpongeBob also gives Sandy a hug] Howdy, SpongeBob.

SpongeBob: Sandy caught the monster! [everyone cheers and picks up SpongeBob and Sandy and bring them into town]

Sandy: I didn't know I'd be missed so much. Golly, maybe I should go out of town more often.