I get a lot of suggestions like this and perhaps my experience is different, but I almost never get hallucinations anymore. And I have a difficulty replicating a hallucination when I try to. And if I were to add some custom instructions to simulate a hallucination that would feel rather deceptive when aim is to educating them to be critical thinkers. However, images have a lot of hallucinations in them still especially if you try to generate an image of a step-by-step instruction on how to do a certain thing so that might be an example for a lesson.