jackaman
A Jackaman is a stubborn, brainy lunatic who won’t quit until they crush you. They lead everything and make you look like a fool.
My mom is a Jackaman. She cleaned the whole house while I was still eating breakfast.
My friend is a Jackaman. He ran a mile before the bell even rang.
That guy at work is a Jackaman. He took over the project and left me with the trash.