[A_PLUS]

I dont think I like the call, but its not worth criticizing, b/c I'll admit I may be wrong. I think another important factor people havent mentioned is the equity you think you have with your 55 without a set.

CO call is scary. He made a BIG call with the original early positon raiser still to act. It seems like you thought highly of this players game so far. Here is what we know. He has a good hand. He is not afraid to see a flop. What hands would you make this play with? AA-QQ, AKs, AQs? Thats about it. I would reraise with a much wider range of hands than I would call with here.

Even if you extend the range, you arent going to have him playing 22 here.

So, two scenarios
1.) He has a higher pocket pair than you. If this is the case, you have close to 0 equity without a set. If you hit your set, you are only going to get the full reward if he has an overpair.

2.) He has two OCs. Now you have a good amount of equity without trips, but you are only going to get the rest of his money if you hit your set when he hits TP or better.

So the pot odds (including implied) are a little decieving.

That being said, I think it is a weak call after thinking about it for a few minutes. In the heat of battle, it isnt a weak enough call to ruin you. IMO