[Wahoo73]

Hmmmm...this is interesting.

I'm going to assume that villain in this hand would not 3-bet the BI unless he had a buried pair bigger than the Ts that Seat 4 is representing, or at least had Ax spades. (Personally, I would not 3-bet the latter, but I know some players would.)

Subsequently, given villain's actions on 4th and 5th streets, I think we can rule out him having buried Ks and buried Js, and since you catch Qs on 5th and 6th, it makes it highly unlikely that villain has buried Qs.

Therefore, by the time you get to the river, I think villain's most likely hands (in order) are either As over, a spade flush (probably AK high), or trips (presumably trip As).

IMO it's a close call as to whether you 3-bet the river or just call, but since you beat two of his most likely hands, I think you 3-bet it.