from www.tmz.com – Spencer Pratt may be in possession of a sex tape after all — one that doesn’t feature himself — because Playboy Playmate Karissa Shannon is threatening to sue Pratt over some private XXX footage he allegedly stole from her home.

Karissa’s lawyer fired off a letter to Spencer — claiming that he is in possession of footage that was “taken from [Karissa]” and “contains private materials” featuring herself and boyfriend Sam Jones.

Shannon demands that Spencer return the footage ASAP — or else she’ll sue his pants off.