Glowfly

Glowflies are tiny bugs that spawn from exotic flowers and will fly around aimlessly. They produce a ring of light around them and drop nothing when killed

Note that Glowflies can spawn during the day, but cannot be targeted by the player. This could mean that Glowflies are not meant to spawn at all times of day. Creatures like Pogs, however, can be persuaded to attack and kill glowflies at any time of day.