Ladder Greaser
A person who thinks they're on top of the Corporate Ladder, but they're just a greasy cheater who can't stay up there and ends up falling flat on their face.
He thought he was on top of the ladder, but he fell because he was too greasy.
She got promoted with her boss, then got fired when she slipped.
He was a cheater who thought he was on top, but the ladder was too greasy and he fell.