PlunderChess

PlunderChess is a commercial chess variant, first sold in 2004, in which the capturing piece is allowed to temporarily take the moving abilities of the piece taken. The game is played with colored plastic rings to mark which abilities have been adopted by pieces.

Rules
The so-called plundering occurs when a chess piece captures an opposing chess piece and "plunders" or "acquires" additional moving capabilities directly from the piece it just captured. Plundering is optional and may be declined by the player making the capture. When plundering is elected, the capturing piece "couples" or "attaches" to itself a vest that corresponds to the moving capabilities it is acquiring from the captured piece. The plundered vest must give added moving capabilities to the piece that wears it or it will not be allowed to plunder. This means that a queen can never wear a rook vest because a queen can already make the moves of a rook and a rook vest provides no additional benefit to the queen. All pieces may plunder a pawn vest in order to gain the ability to capture via en passant. Additionally, pieces with a pawn vest, besides the rook and queen, gain the ability to move forward 2 spaces as long as it is on the second rank; this also allows that piece to be captured via en passant, whether by a pawn or by a piece using a pawn vest. However, it is important to note that a King with a pawn vest may not use a pawn's double-step move option if it would result in the king being able to be captured via en passant.

The added moving capability provided by a plundered vest may be used one time only on any future move: i.e., the plundered vest may be used on its very next move or carried around and used later in the game. After a vest is used to move a chess piece on the board, it must be returned to the stand out of play. No more than one plundered vest is allowed on any one piece at a time. If a chess piece with a plundered vest makes another capture, it may upgrade to a stronger vest. If a player captures a piece with a vest, that player may take the vest it wears or a vest that represents the captured piece.

The pawn with the vest can use it to reach the last rank. In this case the pawn gets immediately promoted. However, the pieces with pawn vest cannot promote, nor can they promote their vest. The pawn can also move to the first rank by a vest move. But it has double-move capability only when moving from 2nd to 4th rank.

A piece with a vest can give a check (or eventually checkmate) to the opponent's king using vest-move power.