Just an old puzzle, the white pawn promotes to a black knight and it's mate.
the white pawn promotes to a black knight????
^Yes indeed. Legend has it that this puzzle was composed before it was an official rule that one could not promote to a piece of another color and the puzzle was made to convince people that an official rule should be made.
Yeah the solution is for white to promote to a black knight. I've already seen a puzzle like this before:
Where the only way white can mate in 1 move is to promote to a black knight.