This is the greatest Black Gambit. Please let me know it's name.

Here is the game:

Duplicate thread
Schilling-Kostic Gambit.
White should not take 4 Nxe5, but rather 4 Nxd4

This is the shittiest gambit I know tbh

4.Nxe5 is a mistake because white loses a piece if black plays correctly though White has 2 pawns and an attack as compensation. And yes, it's not a true gambit for the aforementioned reason but it isn't sound.