Bulber

Bulbers are anglerfish-like enemies that first appear in New Super Mario Bros. Wii. Like real anglerfish, their bulbs illuminate any darkness around them, similar to Jellybeams.

New Super Mario Bros. Wii
In New Super Mario Bros. Wii, Bulbers only appear in World 8-4. They swim freely in the water, illuminating the area around them. They can be defeated by attacking them with a fireball, by freezing them or by running into them with a Star, although this is not necessary and perhaps even detrimental due to loss of illumination. Bulbers are very passive and will only hurt Mario if he touches them.

New Super Mario Bros. U
Bulbers reappear in New Super Mario Bros. U where they act exactly as they did in the Wii game, appearing alongside Jellybeams in Deepsea Ruins of Soda Jungle. However, they come after the Jellybeams this time. They do not reappear in New Super Luigi U.