AKs versus large overbet.

[HeroInBlack]

I call so fast I sprain my finger.

The only hands I can see someone legitimately making this move with are middle pairs, where he knows overcards are going to flop and he doesn't want to guess what you have postflop. So, yeah, you're probably getting in with the worst hand, but the pot odds warrant it.

Alternatively, folding leaves you very close to being a short-stack a point in the tournament where aggression is going to rule without enough chips to be aggressive.

And, given the buy-in, I wouldn't be shocked at all if villain has AJo or something like that that you dominate, especially if you have been stealing a lot previously.