Witchycology is the 25th episode of Sabrina's Secret Life.
Plot
Sabrina and Maritza make people sign a petition inviting a professional skateboarder, Ricky Speed, to Greendale to do a charity event to prevent pollution and littering. The charity event is a success, and as a reward to Sabrina and Maritza, he teaches them to ride the half-pipe. Cassandra ruins Maritza's performance by causing her to blow away in the sky. Sabrina saves her and blames Cassandra, who also happened to be littering. She goes away from the event with Olivia to watch Hay McGoblin perform his skating event in the Netherworld. Hay passes around cans of toxic waste, which causes all of the witches in the Netherworld to turn into stone. This in turn leads all the magic in the Netherworld to disappear: Olivia's plan to take over the Netherworld. Sabrina and Maritza (who believes it to be a dream) go to the Netherworld to help restore it and destroy Hay and Olivia. The toxic waste cans cripple Sabrina's magic, but they finally succeed when Hay gives in, and Olivia is defeated by a spell Sabrina cast which turns her into stone.