Dormwreaker
Similar to a homewreaker, it describes a person who frequently stresses or destroys relationships in undergraduate universities by engaging one or more members of the relationship in conduct unsuited for traditional monogymous college dating.
"So I heard Becky was hanging out with Nick the other day on his futon and they were getting pretty cozy."
"Seriously? Nick is dating Becky's best friend. What a dormwreaker."
"Seriously? Nick is dating Becky's best friend. What a dormwreaker."