Pool Party Karthus
Model (credit to Krizalid):
A flying corpse with long grey hair wearing blue shorts and a lifebuoy which looks like a duck. Oh, oh, and his book will be a summary of rules about how not to drown XD A really paranoid kind of lich, isn't he? XD
Animations:
Q: water balloon that explodes W: a line of water with boas instead of pillars at the two ends E: (might have to think about it, maybe just a moving pool with rubber ducks :) R: super-mega-death-aqua nerf gun shooting from the sky for each enemy