One of the scariest 'Dr Horror Stories' might be the ones involving haunted hospitals. The idea of a place meant to heal being filled with malevolent spirits is truly frightening.
Well, those 'Dr Horror Stories' that deal with cursed medical experiments can be really terrifying. Imagine doctors using unethical methods in the name of science and creating something that goes horribly wrong. It's like a nightmare come to life. For example, an experiment that accidentally releases a deadly virus that turns people into something inhuman. There's also the aspect of the moral decay of the people involved in such experiments which adds to the horror.
The 'Dr Horror Stories' about possessed patients are quite chilling. A patient who seems normal at first but then is taken over by an evil entity. They start to exhibit strange behavior, like speaking in tongues or having superhuman strength. It's the unpredictability and the unknown nature of what's possessing them that makes these stories so scary.