The Caterpillar could be found on the Fantasy Tech web and this is how it would work
As soon as it spawns it's a tiny caterpillar (maybe the size of the baseball bat)
But if it kills 10 bugs (Maybe higher or lower)
It goes into a big cocoon then becomes a big butterfly (the same size as the 2x4 reinforced pillow block)
And it does the same amount of damage as the fly swatter
After 10 seconds it goes back into a cocoon and despawns
I don't have a drawing for it but I would base it off the hungry caterpillar.