Watching a fake hand get stroked can trick your brain into feeling it

Hide a person's real hand from view, place a rubber hand where they can see it, and stroke both in perfect sync. Within minutes most people report feeling the touch as coming from the rubber hand, and flinch if it's suddenly threatened. It's one of the clearest demonstrations that the brain's sense of body ownership is built from matching senses, not fixed anatomy.

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