Replace all the pawns with peasants, they have a 1/20 chance of revolting against their own king and turning into the other players' chess piece.
you can add ONE more piece to the chess board, how does it work?
It can jump over pieces and can cover long diagonals, it can checkmate by itself without any help, it can change the colour of diagonals, like the two black and white bishop
so like a bishop that can jump over pieces?
Also...what'd you say IT CAN CHANGE COLOR TO THE OTHER TEAM?? WOAH :D
How about each player assigning 1 of 8 pawns a special rank before the game begins? That rank, I'll call it invictus, would make 1 pawn for each side immune to being captured until it crosses to the other side of the board. It's just an idea, not my best but not my stupidest either.
NICE
My own idea is that there's a piece, right? that can jump over pieces and go to ANY SQUARE on the board... BUT it can only be used once before it either gets captured or just vanishes after the use.
so like, for example, for a starting move you can just go ahead and capture the queen of the other team... but the piece disappears after you make a move.
you can add ONE more piece to the chess board, how does it work and what is it called?