Mama Luigi is Mario's clone friend and Luigi's clone. He was introduced in Season 1 Episode 1 when they are in the bedroom looking quite bored. So he decides to give Bowser $20 and kidnap Princess Peach and be his hitman.
When Mario & Peach found out that he was actually the clone of his brother Luigi he frees Luigi and Mario said he would hate Mama Luigi forever for what he did to Mario and what he did to his brother Luigi.
He dies in Season 2 when bowser shoots his bomb on his chest and it explodes and Mario never sees him again to episode 10 when Mario kills his undead version of him just like Princess Peach was effected.
He injures and almost kills Bowser with his "Magic Marker Pen" and throws him in a barbacue cooker untill the start of Season 2 of the story.
Mama Luigi was born when the real Luigi finished updating his blog about how he became a character in the worldwide popular Nintendo video game; Super Smash Bros. Brawl, when he told his camera men that he was going to take a poop in the nearby toilet when suddenly he came across a cloning booth which he thought was a massaging booth and when he came out Mama Luigi was born.