I was actually trying to use Ettin and Giant Squid for 24 tentacles and a mouthpick, but there was this annoying size restriction. Then I saw the type line...
Also, Chuck's full round is over 2 million, so we need a doubling and another 50,000 or so attacks, or about 57 offhand progressions. So another six legs.
New optimisation challenge: How many legs can we have on one creature?