what is this opening trap called?

Black simply emerges 1 piece up
en.lichess.org/TP4iJXwD

I don't think it has a name, but it's well known from the Cambridge Springs defense. It's not the only trap in the early moves of that opening, either!

It's called the Queen's Gambit Declined, Elephant Trap:
en.wikipedia.org/wiki/Queen%27s_Gambit_Declined,_Elephant_Trap

@WilliamShakespeare correct. @kitty-MeOw how could you not have heard of that before :P

Elephant Trap. pl.lichess.org/study/Of3mcPk - chapter 9