The Crawling Eye is a very quiet and stoic character, only smiling or laughing when he deems necessary. He is extremely sadistic, and will not hesitate to kill one of his henchman just for fun. He also seems to be a masochist, as he revealed to Mario that he gets spikes in his eye on a daily basis to win a bet with Wario and Waluigi, who rules the 9th Dimension.