A manticore would be good. Or a dragon. Or an acromantula.

I'm not fussy as long as it's not too fussy to eat Carrow. As far as getting rid of it after, that's what Gryffindors are for!

Anyway speaking of Gryffindors I'd suggest you all go to the hospital wing and say you're sick, no potion in Madam Pomfrey's cupboard is half as frightening as class with Carrow when he's hacked off. But you're Gryffindors so I imagine talking you into that sort of plan is a lost cause.