Tim Swanson aspires to be a famous magician like his hero Amaz-O. When he's given free passes to see Amaz-O perform live at the Midnight Mansion, he ends up as part of the disappearing act. Tim ends up stuck backstage as the act comes to a close. Tim finally gets to leave when he overhears what he thinks is Amaz-O insulting him, making Tim believe that his hero is a jerk. He decides to steal Amaz-O's magic kit. After messing with the kit, his younger sister Ginny disappears. Tim at first thinks he's turned her into a rabbit, but the rabbit begins to speak with an adult male voice.
The rabbit introduces himself as El Sydney, a former magician and Amaz-O's assistant. He tells Tim that he met Amaz-O when he was a young boy. Amaz-O took him under his wing and made him believe he was on his way to becoming a star. But when he showed Amaz-O a centuries old magic wand, Amaz-O betrayed him and turned him into a rabbit. Amaz-O then stole all of El Sydney's magic tricks to become famous. El Sydney then asks Tim to help him retrieve the wand in exchange for bringing Ginny back. Tim agrees and the pair return to the Midnight Mansion to search for it. Tim finds it and performs the spell to bring El Sydney back to human form. Amaz-O then shows up and tries to tell Tim the truth that El Sydney is actually an evil magician, but it's too late. El Sydney is back to his human form and transforms Amaz-O into a rabbit to perform in his guillotine act. El Sydney then tells Tim that he could become famous as well, and turns Tim into a rabbit as well. Amaz-O promises to find a way to turn them back, but Tim doesn't want to give up showbiz.
El Sydney is very charismatic, but also very manipulative, especially when it comes to tricking Tim. He is also very evil and deranged, gleefully taking his revenge on Amaz-O for years of being turned into a rabbit.
- El Sydney was an original character created exclusively for the Goosebumps television series and takes on a role similar to that of Amaz-O from the original story.