folie (noun)

1. The intricate patterns and whimsical designs of the building's exterior exhibit a folie-like quality.

2. The main character in the sci-fi novel has a folie that causes him to hallucinate alternate realities.

3. In some religious traditions, possession by spirits is considered a form of folie.

4. The magical realm in the fantasy novel is filled with enchanted beings suffering from various folies.