Shakey's Pizza is based on a real restaurant franchise and was first seen in the Season Five episode, "Kenny Dies".
Background[]
In "Kenny Dies", Eric Cartman's love for the restaurant inspires him to make another for himself using the stem cells. This plot of his was later referenced in "The Death of Eric Cartman".
In "Asspen", Butters Stotch compares learning Thumper's "Pizza / French Fries" skiing technique to eating at Shakey's.
In "Up the Down Steroid", Cartman is awarded with the "Spirit Award" for coming in last place at the Special Olympics. He is upset at first until he hears that the prize includes a $50 gift certificate to Shakey's.
In "Stanley's Cup", Stan Marsh mentions visiting the restaurant after a big hockey game.