Duck


https://www.chess.com/variants/duck-chess
It is a silly variant which has been a trend lately. It has a few different rules (as with all variants), but the most notable is that after each move, the player selects the duck piece (a brick) and places it on a different, empty, square. The strategy and tactics are clearly different because you can do things like use the duck as interference (to avoid exchanges etc.) or literally block off an outpost for a move.