O BLAARGAGG!?!
When your brain short-circuits and you can't think of anything to say. You just scream 'O BLAARGAGG?!?,' then bolt like a coward.
Teacher: 'What did you learn today?' Me: 'O BLAARGAGG?!?'
Friend: 'What's your favorite color?' Me: 'O BLAARGAGG?!?'
Mom: 'Did you eat your veggies?' Me: 'O BLAARGAGG?!?'