What-a-mess is kinda cute to me and he has that cute voice. In case you don't know, his voice actor, Ryan O'Donohue was also the voice of young Kovu in The Lion King II: Simba's Pride.
funny this isn't the first tme charlie adler voiced a rat character, back in 1992 he did the voice for jammet the rat from the short lived series Capitol Critters.