This Time, I'm the Fool
My roommate was a classic bimbo.
When I went to arrange a jogging meetup, she mistyped it as a hookup and sent it straight into the group chat, then burst into tears and claimed she didn't know how to retract the message.
When I went to meet my jogging buddy, she told everyone that she ran into my "hookup buddy." At the end, she even covered her mouth and giggled sweetly, saying, "I always mix words up."
After a few stunts like that, my reputation was utterly ruined, and the entire class shut me out.
Later, she used her "clumsiness" as an excuse to spike my milk with sleeping pills, causing me to miss a major exam. She even dropped toxic bacteria into my water cup and killed me outright.