1) Not to be confused with foe, FOE is an acronym to describe that type of enemy in a video game that is too strong to be fair and often winds up killing you when you encounter it. (Fucking Overpowered Enemy).
2) Title of a song in a video by Iosys. Now found on Youtube!
1) Player 1: Hey, look, there's an enemy all alone out here!
Player 2: Wait, wait! I've fought that thing before. It's a total FOE. Let's sneak past it and hope a fight doesn't start.
2) Has its own definition, F O E!