|Voice Actor||Phil Morris|
|First Appearance||Black Monday|
- "Bad copy! Bad copy! Bad copy!"
- ―Doc Monday in Black Monday
He has an eye patch over his left eye which covers up his scar as compared to Doc Saturday's scar on his right eye. By accident, he helped Zak Saturday figure out who was his real mom. He called Zak Saturday "Bad copy" a lot. He is not very smart, saying nothing but "Bad, bad, bad," when he was left behind by Zak and Komodo. Like the rest of his family, he is hated by many people in the Smoke Mirror of Tezcatlipoca. He is left behind when Zak Monday and Komodo Monday escape at the end of Black Monday.
He can't even come up with an effective insult, telling the good Doc while they were fighting "Blah, blah, blah, blah, smart-talk science!" then blowing his tongue out at him. All Doc could say was "Umm, right back at you?" before punching him about a thousand miles away. As the Mondays family is made of anti-matter, and the Saturdays are made of "matter" so when they got near, the laws of physics stopped working right. Explaining why the good Doc was able to punch Doc Monday around the world, and why the evil one came back around and landed on him. He reappears in Paris is Melting, still stuck in the mirror but at least he got the chance to beat up Zak and Komodo Monday for leaving them. He seems to have a black, fingerless version of Doc Saturday's glove and wears it on his left hand instead of his right. It is unknown if his glove has the same power since he is the complete opposite of Doc Saturday.