Meitantei Conan S20E20 - The Screaming Operation Room (Part 1)

When Kogoro Mouri goes to his alma mater for a "speech", Ran, Sonoko, and Conan end up going with him. Sonsaku Tsujiei, a 4th year student at Beika University, wants Kogoro to look at the haunted house and evaluate its accuracy. When Kogoro takes too long during his speech, Conan, Ran, and Sonoko decide to check out the haunted house themselves. Sonsaku and Hachiya Kiichi (a colleague) escort them into the haunted house only to later play tricks to scare them. When they are in the "Operating Room", Anna Tadami, the victim, is playing the patient during the operation. When the trick is over, everyone realizes that Anna hadn't finished her part. When they try to get her to wake up, Conan realizes she has been poisoned by cyanide.