The Bioluminescence Gene makes it so that entities will occasionally place a light source where they stand.
This light source will automatically despawn after a short period of time, but you can also use the command /genetics clear_bio_glow to remove all nearby Bioluminescence Blocks if that doesn't work.
Obtaining
By default, you can get it from these sources:
- Blaze: 3/12
- Glow Squid: 4/11
- Magma Cube: 4/11