What's the worst villain in the entire property?

[Prowler]

I haven't seen/read everything, so it's possible the worst villain is from, let's say, Rise, IDW or The Next Mutation. I wouldn't know.

So my first thought... the family of hillbillies that fool Donatello and steal the Turtle Van from him in a season 5 or so episode in the Fred Wolf series. I mean, really? At least mad scientists make sense for villains, even if the characters themselves or the execution was not the best. But a family of hillbillies?