50 years ago: Fischer-Spassky, Secret weapons?
After draws in games 14 and 15, Fischer still had a three-point lead in the World Championship match, and the Spassky side was getting nervous. The Champion was fighting hard, but not getting any points. Suspicion arose that Fischer might be using secret weapons: hypnosis, devices planted in the lights or the chairs, and even perhaps assistance from an "IBM" (Russian for "computer" at the time). All this was formally investigated, while Fischer continued to coast.
Source: chessbase.com