Glitches

Lets say you and your opponent who we will call Timmy (he’s such a nice guy)
Timmy moves his pawn forward the battlefield, and lets say you don’t want to trade pawns for whatever reason, so let’s assume you haven’t moved your pawn, so you push it forward TWICE, now your pawn is right next to his pawn, it sounds like you’re good right? But Timmy’s pawn can go behind your pawn, and evaporate it
If Timmy were to do a move, and then you do another move (any move that isn’t en passant or moving any of those 2 pawns) Timmy will loose the ability to do en passant, either you do it at the moment, or you loose the opportunity and instead make a different move