In the episode Tak: the Hideous New Girl, Rob was sent by Ms. Bitters to an underground classroom, along with Brian, so that Tak could sit in his seat. However, after Tak's departure, he returns to Bitters' classroom with no ill effects.
Rob has a thin face and noticably large forehead; the forehead being the possible reason for Dib's claim of his father being a yeti. Because of this abnormal feature, his eyes are not visible. However, his most distinguishing feature are the two orange spikes of hair that stick straight up on either side of his otherwise-bald head.
Role in Invader ZIM
Rob is one of the many people who mock Dib for his claims of Zim's true identity. This occurs in all episodes set at Skool. This was most featured in A Room with a Moose, when he walked away miserably when Dib was sitting in the same chair as him. He sides with the other Skoolchildren when they thought sitting on Dib's side of the bus "didn't sound cool" and he agreed with Sara that the 'surprise field trip' was "almost as stupid as Dib". In The Frycook What Came From All That Space, Rob agreed with Poonchy's point that "aliens don't like wearing pants".