Roly-Poly resembles a sky blue-colored sphere with dark blue-colored, Kirby-like feet. For facial features, it has a cat-like mouth, the top of which extends over the bottom part. Roly-Polys also have small, black, circular eyes with white pupils. Other than these aspects, however, no other features are visible on its body.
Roly-Polys' main method of attack is to ram into Kirby while rolling. To do this, they continually chase him; they alternate between rolling a moderate distance in Kirby's direction and taking a short rest. When they roll, Roly-Polys are affected by gravity, either speeding up if traveling downhill or being pulled backwards if traveling uphill. Roly-Polys can also attempt to hit Kirby by leaping high into the air. This attack seems to occur at random, but it is preceded by the Roly-Poly speeding up.
Roly-Polys are likely named after the woodlice of the same name. Though they bear little resemblance to Roly-Polys, those insects can roll up their bodies in the same way Roly-Polys can.
- Mr. Frosty's earlier sprites shares a passing resemblance to Roly-Poly, but no evidence supports any form of relationship between the two.