ka-doink, boink
A word you shout when someone makes a mistake so obvious it’s like they’re blind and stupid. You might even throw a banana at them if they keep doing it.
My friend said, 'I can’t believe I forgot my lunch.' I ka-doink-ed him and threw a banana at his head.
My mom said, 'I can’t believe I wore my shirt backwards.' I ka-doink-ed her and made her do 10 sit-ups.
My teacher said, 'I can’t believe you didn’t bring your book.' I ka-doink-ed her and took her book and threw it out the window.