Does anyone know what this weird opening is called?


1.e4 b5? is a blunder because after 2.Bxb5 Black's down a pawn with very little to show for it. You unfortunately did not watch for CHECKS and CAPTUREs.
As far as the naming of things, sites alternatively call this unsound wing gambit the Polish Gambit (1.b4 is the Polish and 1.d4 b5 is the Polish Defense), and the Larson Gambit.