Firefly

The Firefly is a critter that gives off a tiny amount of light. Fireflies have only 5 health, and can be damaged by other mobs including the player, which almost always results in their instant death.

Fireflies will spawn anywhere on the surface at night, except inside houses. They can be caught with a Bug Net to be carried around and released later, or put in a bottle to be used as furniture and a light source. The bottled firefly is animated and moves around inside, and cannot be released once crafted.