Dib and Gaz were both at school, it was around lunch time. While Dib was complaining to Gaz about Zim and the fact he's an alien and nobody believes him. Meanwhile Gaz was playing games while eating lunch Dib: "He's obviously an alien! He has green skin!"

Gaz: ". . ."

Even their father didn't believe Dib, believing him to be insane.