baaarstard
A baaarstard is someone who takes the fun out of everything. They're like a boring movie that doesn't have any explosions.
My neighbor is a baaarstard. She told me she'd let me play on her Xbox, then made me do 100 push-ups first.
My cousin is a baaarstard. He said he'd give me his toy, then broke it in front of me.
My coach is a baaarstard. He said he'd let me skip practice, then made me run laps anyway.