Hm, Maratoad? Too obvious perhaps... And then Puppille might not be obvious enough.

It really is. It's a great drawing to yes. Yes, it is indeed from "that weird Roger Waters thing"--which is actually much better than it sounds, in the original French version, anyway. (The English version has the annoying habit of changing great lines like "régner est un crime immense" ("to reign is an immense crime") to "to be king is a sacred trust." >_>) The art is by the librettist's wife.