Creeks & Crawdads! was one of the wave of satiric mid-1980s roleplaying games. Parodying D&D's rules and the post-apocalyptic genre, C&C postulated a world where humanity wiped themselves out, along with all the higher lifeforms. The most advanced species remaining, the crayfish, is struggling towards intelligence with a little help from the mutagenic radiation, but isn't quite there yet. PCs take the role of these crawdads. The system has 9 characteristics, is class based (fighter, tool user, thinker), and uses a dice pool. Might be the first RPG that explicitly advertised itself (on the cover, no less) as a "beer and pretzels roleplaying game".