Liquid Kids is a bizarre-but-fun platform game by Taito, first released into video game arcades in 1990.
It features a cute, cartoon platypus (called Hipopo) as the playable character, and who can throw ‘water bombs’ at his opponents to soak and damage them. Once soaked, his enemies can then be kicked to be destroyed completely. Enemies left un-kicked will eventually dry out, recover and go on the attack again.
Liquid Kids does display shades of Parasol Stars‘ gameplay (and Rainbow Islands, if you count the “GOAL IN!” text), although Parasol Stars came a year later than Liquid Kids, in 1991. So Liquid Kids may well have been an influence on Parasol Stars. Who knows? Who cares?!
Liquid Kids is one of those obscure Japanese arcade games that is somewhat unknown, and is always a delight to discover for the first time. If you never played it: hunt it down.
More: Liquid Kids on Wikipedia