gaigai
the sound of your brain short-circuiting because you're too dumb to come up with something smarter.
'Gaigai... I don't even know what I'm saying.', said to your crush during a text message.
'Gaigai... this is the worst.', said after your dog ate your homework.
'Gaigai... why is this happening?', said to your teacher when you failed the test for the third time.