And if I could have just any beastly power, I'd pick something really creepy. Like amoeba powers, to ooze around people and eat them. Or virus powers: I touch people and they start bloating with Dodom-babies until they burst, releasing my offspring. People adopt the cute little babies, and when they're mature, they each infect new hosts. Dodompocalypse!
I like it but I'd want to have tentacles. I'd want to be a morphing hentai tentacle rapist and impregnate women everywhere with my phallic tentacle appendages. Being able to spurt gluey slime would be good too especially if it had a precision applicator to fix stuff. I'd hire myself out as a handyman and bru-hahahaha!
"... one of the finest, grumpiest most cynical people in the known universe."