ka-cha
A person who acts like a brain-dead donkey. They make bad choices, say stupid things, and can't be trusted to do anything right. Cha-Ka is like a broken toaster that burns your toast every time.
My friend is a Cha-Ka. He wore socks with sandals to prom and tried to dance like a robot.
My sister is a Cha-Ka. She failed math and still thinks she's a genius.
My dog is a Cha-Ka. He ate my homework and then barked at the teacher.