GAHGAHGAH
you yell GAHGAHGAH when someone says something so stupid it makes your brain explode
My brother said 'I’m the best at video games because I have 10 thumbs' and I GAHGAHGAH’d him into the couch
When my dad said 'I can beat anyone at chess' I GAHGAHGAH’d him so hard the dog ran away
My friend said 'I can eat a whole pizza in one bite' and I GAHGAHGAH’d him until he cried