I was playing 5-ring this morning and there was this maniac who was shoving all in constantly - I'd say on average once every 5 hands. I had already won a big pot against him when I raised AJ and flopped the nut flush. He called me with a 33.

This time around I raised 3BB on KK - I'm on the button.

I raised 3BB and he called. The flop was

2 9 8

I'm thinking this is great for me, and maybe I am too focused on my own hand because he is such a nut. Anyway, no surprise he shoves like 95BB. I don't think, I snap call. (I have about 3x his stack).

The turn was 5

River was 6

His hand:

J 9

He wins with the flush.

I felt like I played it right, but thinking back I totally missed that he could be on a flush draw. Looking at the hand calculator, I was still a 69.9% favorite, so maybe I'm over thinking it?

First, 3BB is way too small to raise against a maniac. I would either limp, hoping he would raise, and if he does I shove. Otherwise I raise to about 10BB.

As for the hand, I'm a little confused. You say you totally "missed" that he might be on a flush draw. What are you saying? You would have folded if you saw the 2 hearts on board? I don't understand. Of course you hope he puts all his money in on a draw. There's really only one hand you don't want to see on a draw, and that's J T (or 7 6).

I guess I was a little bothered by the fact that I didn't assess what he was shoving because I was so focused on my own hand, which is not good.

I would have raised higher, but he was calling any raise, no matter what if he had a hand he liked. He had called 10BB, 20BB raises already from other players.

Even if you put him on a range of sets or overpairs you're ahead:

ProPokerTools Hold'em Simulation
20,790 trials (Exhaustive)
board: 298
KdKc 53.46% (11,115 wins, 0 ties)
99,88,22,JJ,QQ 46.54% (9,675 wins, 0 ties)

Snap call is correct.

Start putting TT and draws in his range and it's even snappier.

Okay, thanks DD - helpful as always

Interesting.
Discounting draws (which are snap calls with KK and that board), if I could see that villain had a set and I had an overpair I would snap fold.
But now I see that's wrong!

Don't we just have two outs to improve though?

EDIT: Oops, I see that your range includes overpairs smaller than KK too. I guess we are always in bad shape against sets.

Yeah, obviously stuffed against a range of sets only, but I'm guessing this particular villain is getting it in way wider than that.

Exactly, so raise higher. You want him to call huge raises when you have KK.

If we are honestly and truly up against a bonafide maniac who is just shove-shove-shoving all day with a super wide range of hands...

then we should always feel good about betting, raising, and definitely snap calling a shove from the maniac when we have TPWK or better.

Seriously, i'm never even thinking twice about it and if this just happens to be the one time the maniac has a monster hand... meh... big deal.

its just not profitable folding to a maniacs shove when you have ANY hand of value...

+1
Happened to me at my local casino donkament last night. Villain was getting short stacked and shoving whenever he saw weakness.
I was in the BB with A-8, 4 limpers and I checked. Flop came down A-Q-x, (blank was 5 I think) three checks, agro fish donk person shoves I insta call, 3 folds and he flips over Q-2 like its the nuts.