When should I have KNOWN I was BEAT??

Does anyone put him on a set here? Seems like an extreme overbet by villain? I don't think I let 2 pair go here. The only thing I can put villain on would be 2 pair. He (villain) was awful passive and I think incorrect on the flop. He has to figure an A,Q or T would have potential of scaring hero away or make hero's hand. For this reason I would presume he caught 2nd pair or was bluffing and I have to call.