The hallmark symptom of these mushrooms are Lilliputian hallucinations. This is a clinically defined psychiatric condition characterized by the perception of numerous tiny human, animal, or fantasy-like figures in one’s environment. They’re often very realistic, three dimensional figures said to be colorfully dressed, very mobile, and interacting with the physical world—like climbing up chairs or tables, or clinging to surfaces.

(for anyone else wondering, it's a book, 1Q84 by Haruki Murakami, from 2009-2010)

Every time this topic comes up and the comments are full of discussions about the little people I think of it. I do wonder if Murakami was inspired in any way by similar discussions.