Eleventh Doctor-Gantok chess match

The Eleventh Doctor-Gantok chess match was a game of live chess between the Doctor and Gantok.

Origins
Whilst hunting for information on the Silence, the Eleventh Doctor met with the Teselecta which was disguised as Gideon Vandaleur, an agent for the Silence. The Doctor asked for one piece of information from the Teselecta: the Silence's weakest link. The Doctor was pointed in the direction of Gantok. (TV: The Wedding of River Song)

The match
The Doctor challenged Gantok to a game of live chess in which every time one moves a piece, the current in it increases. The game reached a point where Gantok's only legal move was the queen. He had already moved it twelve times, however. As a result, over four million volts ran through it. Faced with almost certain death, Gantok asked the Doctor to concede. The Doctor complied in return for information on the Silence, although Gantok told him they would kill him if they found out. Gantok also told him that he could take the Doctor to see Dorium Maldovar, even though he had been beheaded on Demons Run. (TV: The Wedding of River Song)

Aftermath
True to his word, Gantok took the Doctor to the Seventh Transept, where the Headless Monks stored those converted to the order. Whilst there, Gantok attempted to kill the Doctor in revenge for besting him at chess. However, he fell through a trapdoor that led him to a pile of ravenous skulls which then devoured him. (TV: The Wedding of River Song)

The Doctor would later discover the true purpose of the Silence he encountered: members of the Kovarian Chapter that had travelled back in time to prevent the Time Lords from returning on Trenzalore. (TV: The Time of the Doctor)