At a regional chess tournament earlier this month, one competitor was allegedly caught on film lacing her opponent's board with liquid mercury.
https://www.wired.com/story/russian-chess-player-poison-board-mercury/?utm_source=dlvr.it&utm_medium=blogger
https://www.wired.com/story/russian-chess-player-poison-board-mercury/?utm_source=dlvr.it&utm_medium=blogger