Caterpillars appear as green worms with legs, hence the name caterpillar. Caterpillars have four segments with two legs below each segment. The head appears as a separate segment, with a mouth, antennae, and eyes.
Caterpillars are usually found alone, however, there are two areas that have two caterpillars. Caterpillars move horizontally, turning at walls or a set spot. While caterpillars will kill Brain and Sporty small fries, Skeleton is invincible to it and Warrior small fries will kill the caterpillar on contact by punching it. After being attacked and killed, it will deflate and then disappear from the screen.