Superb Harry Potter/HP Lovecraft Mash-Up by Nik Holmes

Excellent HP/HP mash-up by Nik Holmes (ZombieDollar Creative) available 4/28 @Teefury.

Actually I'm kind of surprised this isn't a more common fan art theme.
More cool horror themed art & tees available at the ZombieDollar Creative's RedBubble Store.
Including this excellent Word of Warcraft/Cthulhu parody! Via Shirtoid.