Wormy is a caterpillar which is shown in the episode of the same name. Wormy is found inside the Treedome when Sandy leaves from a Holiday. Wormy becomes SpongeBob and Patrick's best friend. They play a variety of games together including hide-and-seek and tag. Wormy gets given a badge that says best friend (meaning SpongeBob and Patrick’s best friend). One night when SpongeBob and Patrick are sleeping wormy turns into a cocoon, then a butterfly. The next morning when SpongeBob and Patrick come back there is no Wormy, he is a butterfly. The "Monster-butterfly" of Bikini Bottom until Sandy "rescues" the town. Wormy caused the whole town to be destroyed including the signs and stores...
The life of Wormy is only seen in Wormy and his life as a caterpillar was short until he turned into a butterfly but he was not seen any more after that.
He is green as a caterpillar until he transforms into a butterfly. When he turns into a butterfly he has:
- A black/brown body.
- Orange wings but with a black outline.
- Black Marks on the wings.
- The close up of the butterfly shows the head of a buzzing horsefly, which some people hate.
- Maybe a monarch butterfly, another kind of poisonous orange and black butterfly, or the kind that disguises as one.
- Wormy has also been seen in some SpongeBob video games.
- Wormy has been in many places in Bikini Bottom, but he never went into SpongeBob's House, Squidward's House, Plankton's House, Mr. Krabs' House, Mrs. Puff's House or Patrick's House.
- Wormy or Sandy's other pets have never been seen again in the series.
- Wormy is a parody of Mothra, a moth monster in the Godzilla films although attacked like Godzilla.
- It's butterfly species form is probably Danaus plexippus (Monarch Butterfly).
- Wormy looks much more like a worm than a caterpillar.
- During the news flash about the "monster," the live-action stock footage shown suggests that Wormy is actually a female butterfly, due to the thick veins on its wings.
- The picture for Wormy the butterfly was a real butterfly.
- Wormy lived from February 7, 2001 - October 4, 2003.