facepalming
The only thing you can do when someone says something so dumb it makes your brain scream, and you just slap your face like you're trying to kill your own thoughts.
'I just told my dad I'm a wizard.' *facepalm*
'My pet fish said I'm a noob.' *facepalm*
'I tried to be cool and now I'm just a mess.' *facepalm*