South Park: Season 3, Episode 3

3 - 3: The Succubus (a.k.a. Chef's Mama)

The boys don't like Chef's new girlfriend, so when she and Chef announce their engagement, the boys set out to prove she's a succubus. Chef's parents arrive for the wedding, and tell they boys about the time they met the Loch Ness Monster. Cartman visits an evil optometrist who makes his life a living hell.