Karkat Vant-fine-ass aka Werecrab found out he was part wolf, part crab on accident, on a walk on the beach one night while drunk and under the influence of halluciagenics. Turns out, he was just a werewolf though and ate 48 crabs that night. But legend goes that he also has crabs, which he wouldn't have gotten if he didn't pursue the raving lunatic, Kankri Vantass. Legend also has it that if you do a crab walk on a full moon that you will summon this rare creature they now refer to as the Kar-Were-Crab.