Karissa Shannon

Spencer Pratt has unearthed a girl-on-girl tape featuring Heidi Montag and Playboy Playmate Karissa Shannon ... sources tell TMZ. We're told not too long ago Spencer was at the Malibu house he once shared with Heidi ... moving out some of his stuff. Sources tell us Spencer came upon a camera with…

Playboy Playmates and biological twin sisters Karissa and Kristina Shannon, 20, got a lot closer at the Playboy mansion this weekend ... and shared a tender open-mouth kiss with each other. It's OK to love your sister ... but is it really OK to LOOOOOOOOVE your sister?