|"Leela and the Genestalk" (7ACV22)
Before he was cured, the crew found him imprisoned in a secret room in Mom's flying castle. Leela tried to help him by releasing him, but he started to chase them. They managed to escape through a sink drain.
Mom later took the cured Stan to Planet Express, to show Leela that genetic engineering can do good.
Leela: It's another one of Mom's genetic monstrosities!
Stan: Fee-fi-hi. [laughing] I'm Stan.