VIP Chess

Secretly mark one piece; if it is captured, you lose instantly.

Before the game begins each player secretly marks one of their non-king pieces as the VIP (wait past 30 seconds and a random one is assigned). Capture the enemy VIP and you win instantly, but nobody knows which piece is marked until it falls. A VIP pawn that promotes keeps its VIP status, capturing the king still wins as usual, and both VIPs are revealed whenever the game ends, however it ends.