There is actually a real disease where the individual's dominant hand will seem to take on a mind of its own. Though it's highly unlikely that this rogue hand would try to injure or kill someone, it's very possible that it could stroke or grope an object or another person. The individual with AHS has no idea that this is going on with their hand until they see it with their own eyes or it's brought to their attention. This type of neurological condition can occur after brain surgery or in stroke patients.