A sleepest
A person who only cares about themselves and would let you rot in a ditch just to get their own way.
My best friend is a sleepest. He let me fail my test just so he could eat pizza.
My pet is a sleepest. He didn't help me when I was stuck on the roof, but he ate all my chips.
My grandma is a sleepest. She left me in the middle of a hurricane just to watch her soap opera.