Belfly

"Thin wings hide a highly volatile belly. Will give its own life to protect its territory. An angry creature with no regard for its own life. A creature without fear... can it truly be called "prey"?"

Belflies are enemies in Hollow Knight. They are quick, highly volatile flying creatures who dive at prey with no sense of self-preservation.

Behaviour and Tactics
It hangs from a ceiling, emitting a high-pitched squeak. Listen carefully for this sound as it is usually found in dark or secluded places, where spotting it usually means that it's too late to avoid contact with it.

Upon seeing the Knight, it emits a louder shriek, exposes its glowing belly, then swoops down on the Knight, exploding on contact and dealing two masks of damage.

Its homing is limited to a wide arc about 90 degrees below it, after which it will continue in an arc until making contact with the environment or the Knight. Dodge away when it dives in and let it explode against the surface it impacts. The blast also instantly kills any enemy in its area of effect.

It is possible to kill it before it dives as it dies in one hit even with the un-upgraded Nail; however, timing this is difficult. Spells, Nail Arts, and Grubberfly's Elegy can be used to dispose of it from a distance.

If a Belfly kills itself, it still will count towards its entry in the Hunter's Journal.

Location
They can be found mainly in the Royal Waterways and Kingdom's Edge; however, they can also be spotted in smaller numbers throughout the City of Tears and in the north part of Ancient Basin. Belflies are also in the Colosseum of Fools, during wave 6 and 7 of the Trial of the Conqueror and wave 4 of the Trial of the Fool.

Trivia

 * It can be pushed back from the Knight to avoid damage by using the Dream Nail.
 * Its shell will not drop if it is killed before it reaches the ground.

References

Wammfliege Звонокрыл Brzusznik Belfly