What are some anime that are adapted from an adaptation of the source rather than the original source?

The title is pretty self-explanatory. What are some anime that are adapted from a manga, light novel, novel, game, visual novel, etc. that itself is an adaptation of another piece of media? I always find it curious when this is done. It’s fun thinking about why they did they chose to adapt the anime from an adaptation rather than the original. I’ll add a few that I know of in the comments.

Edit: As u/Abysswatcherbel points out, anime adaptations of light novel adaptations of web novels are too common to be interesting to point out.

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