Who's Got the Greatest Mom In The World?

"Who's Got the Greatest Mom In The World?" is song sung by Eric and Liane Cartman in the Season Ten episode, "Tsst".

Background
South Park Elementary counselor, Mr. Mackey calls Liane Cartman into his office on the charge that Eric Cartman handcuffed Billy Turner's ankle to the school flagpole and then gave him a hacksaw to free himself. While discussing her sons worsening violent behavior she begins to cry. Cartman tries to lighten the mood by singing.

Lyrics
Cartman: You're a great mom. Who's got the greatest mom in the world? I dooo. My mom is number one in my heart. It's true! Mrs. Cartman and Cartman: My mom's the best mom, better than your mom. It's singing together in harmony.