Stroke a fake hand in sync with a hidden real one and the brain adopts the fake

In a 1998 experiment, people watched a rubber hand being stroked with a paintbrush while their own hidden real hand was stroked in perfect sync. Within minutes, most reported feeling the touch as coming from the rubber hand itself, and flinched when it was suddenly threatened. The brain's sense of body ownership turned out to be built from matching senses moment to moment, not fixed to your actual flesh.

— Matthew Botvinick and Jonathan Cohen, Rubber hands 'feel' touch that eyes see — Nature, 1998