Dennis Rafkin is from the movie Thir13en Ghosts. Unless you'd like him to suddenly and painfully know everything about your character, please don't touch the happy fun Dennis: physical contact causes him anything from migraines to muscle spasms to seizures, during which the entire life of the person who has touched him, even through clothing, is downloaded forcibly into his brain. Of course, if you would like that to happen: touch away, and tell me what Dennis would see.
Dennis is also a ghost now. Such fun for him! He's tangible, and appears entirely normal, unless his energy becomes drained or your character is sensitive to ghosts, in which case he appears remarkably more dead, with a large bloodstain across the right side of his head and all the perfumes of Arabia will not sweeten that little hand. Despite being dead, his abilities still prevent him from being able to touch anyone (because of course they do), but he is now able to stand the presence of other spirits.