Shark-kin
From 1d4chan
Shark-kin are a race of humanoid sharks native to the Dungeons & Dragons world of Mystara. Appearing in the splatbook "The Sea Peoples", they are essentially a non-evil (or at least less evil) version of the sahuagin, spending most of the year with a merfolk-like body structure, but they change their tail into a pair of legs and come onto the land during the breeding season... which brings them into conflict with humans when they colonize the sacred islands where the shark-kin come to mate.