Season 1, Episode 19: “The Ghost of Suite 613”
Amidst word of a potential ghost in Suite 613 and not wanting to back down from a challenge, Zack, Cody, Esteban, Maddie, and London decide to enter the suite and confront the ghost after learning the backstory.
A mere ploy to encounter the ghost turns into a nightmare as each of the visitors gets taken one by one in unrelenting and shocking fashion. Though scarily disappearing turns out to be a prank on Zack, there is full seriousness at the conclusion of the episode when the ghost herself makes an appearance and walks into a wall!