Ripped by Random Talking Bush of the Spriter's resource.
The Inflation ball (also called as "worm ball") is an attack used by Earthworm Jim in ClayFighter 63 1/3 and ClayFighter: Sculptor's Cut.
EWJ somehow inflates his super suit and rolls at his opponent and yells "Whoa nelly!" This move can be peformed with down two times + kick, being the only move performed like that in the game that's not an Overhead Attack (a common move made the same way, but with punch instead kick).