Fly

Entity Image
Base HP	3
Base HP	3
Stage HP	0
Stage HP	0
Entity ID	13.0
Found In

This article is about the fly enemies. For other uses, see Fly (Disambiguation).

Flies are enemies that buzz around the room randomly, but slowly hover towards Isaac. They cannot damage Isaac at all, even by touch, making them completely harmless. However, they can turn into Pooters if they fly around Poop for too long.

Along with monsters like the Gapers and Spiders, Flies are one of the most commonly-encountered monsters and appear in numerous different types.

Variants

Attack Fly

Entity Image
Base HP	5
Base HP	5
Stage HP	0
Stage HP	0
Entity ID	18.0
Found In

Attack Flies are red and black flashing flies that will chase Isaac, dealing contact damage.

Weirdly, while they can easily hit Isaac from the left or right, they have great difficulty hitting him from the top or bottom.

Notes

• The Duke of Flies can spawn larger versions of Attack Flies that have 10 base HP.
• Gurdy can spawn weaker versions of Attack Flies that only have 3 base HP.
• Attack Flies turn into regular Flies if Isaac has Skatole. However, they take a small amount of time to convert into Flies, so it is possible for Isaac to be damaged if the player is not careful.

Ring Fly

Entity Image
Base HP	5
Base HP	5
Stage HP	0
Stage HP	0
Entity ID	222.0
Found In

Ring Flies are a new addition to Rebirth. They are pink flies that, upon entering the room, will cluster together into a circular formation and orbit rapidly while moving towards Isaac. They will hold formation even as flies are destroyed. The maximum amount of flies per formation is 10.

Notes

• Ring Flies are not affected by Strange Attractor and will continue to stay within their current circular formation.

Moter

Entity Image
Base HP	10
Base HP	10
Stage HP	0
Stage HP	0
Entity ID	80.0
Found In

Moters appear as two conjoined Attack Flies. They behave similarly to regular Attack Flies, but split into two Attack Flies upon being killed. The directions the Attack Flies will split off is parallel to Isaac (vertical if Isaac is to either side, and horizontal if he is above or below).

Notes

• If Isaac has Skatole or kills a Moter fast enough, it will not split into two Attack Flies.

Eternal Fly

Entity Image
Entity ID	96.0
Found In	All Chapters

The Eternal Fly is a white-colored fly that can be found on any floor in the game. They usually circle Corny Poop or enemies like Holy Leeches and Hangers, and will not stop circling them until their hosts are destroyed. Before that, they will deal damage to Isaac if he touches them, and they are completely immune to all forms of damage. When their hosts are destroyed, they convert into a modified version of an Attack Fly that regenerates health and can be killed if walked into. Eternal Flies circling Corn Poop do not need to be killed to clear a room.

Notes

• Eternal Flies can be killed by Chaos Card, Little Horn, and Euthanasia.
• Their bestiary entry states that they have 300 HP.

Dart Fly

Entity Image
Base HP	5
Base HP	5
Stage HP	0
Stage HP	0
Entity ID	256.0
Found In

Dart Flies are similar to regular Attack Flies, but attempt to predict Isaac's movements and cut him off.

Swarm

Entity Image
Base HP	5
Base HP	5
Stage HP	0
Stage HP	0
Entity ID	281.0
Found In

Swarms are similar to regular Attack Flies, but appear in tightly-packed clusters.

Notes

• If a Swarm is somehow separated from its group, it quickly moves back to its group when it is able to.

Hush Fly

Entity Image
Base HP	10
Base HP	10
Stage HP	0
Stage HP	0
Entity ID	296.0
Found In	Spawned by Hush

Hush Flies are mainly spawned by Hush and behave somewhat similar to Ring Flies, but do not fly towards Isaac and remain in a fixed path. Unlike Ring Flies, Hush Flies can form other shapes such as polygons. When spawned by Hush they can also orbit it, form a pattern and travel in a straight path, or form a pattern and chase after Isaac.

Hush Flies have a brief period of invincibility when Hush spawns them, making them appear to have more health than they actually have.

Hush Flies can also spawn outside of the Hush fight in some rare rooms. When encountered in these rooms they will continuously orbit in a fixed path.

Notes

• Hush Flies are not affected by the Beelzebub transformation.
• They can also appear in ??? with the use of Red Key.

Army Fly

Entity Image
Base HP	5
Base HP	5
Stage HP	0
Stage HP	0
Entity ID	868.0
Found In

Army Flies chase Isaac, moving in the cardinal directions as they do so. If there are other Army Flies in the room, they will form a single-file line while chasing Isaac.

Willo

Entity Image
Base HP	6
Base HP	6
Stage HP	0
Stage HP	0
Entity ID	808.0
Found In

Willos circle a set distance around Isaac, moving with him perfectly, and firing shots inwards towards him; only one can fire at a time, and the one about to fire telegraphs this by flashing rapidly just beforehand. They circle quickly at even intervals, and can be hard to hit. If there is a Fire Place within the room, they can be guided into it; making this an efficient method of tackling this enemy. They do not deal contact damage.

Notes

• Min-Min can spawn these; some of them behave normally, while some pop out of the ground, launch a volley of shots at Isaac, and disappear back into the ground.
• Mullighouls spawn these occasionally, and spawn 2 more when they die.

Ultra Famine Fly

Entity Image
Base HP	10
Base HP	10
Stage HP	0
Stage HP	0
Entity ID	951.11
Found In	Spawned exclusively by Ultra Famine.

Ultra Famine Flies are flies spawned by Ultra Famine that charge at Isaac on a delay. They come in 3 sizes- small, medium and large.

Ultra Pestilence Fly

Entity Image
Base HP	10
Base HP	10
Stage HP	0
Stage HP	0
Entity ID	951.21
Found In	Spawned exclusively by Ultra Pestilence.

Ultra Pestilence Flies are flies spawned by Ultra Pestilence that swarm around him, blocking shots and dealing contact damage. They also can be spawned by the Ultra Pestilence Fly Ball in Ultra Pestilence's 2nd phase. They come in 3 sizes- small, medium and large.

Gallery

• 

  An Attack Fly on Isaac's Last Will.

• 

  Sketches of monsters for The Binding of Isaac: Rebirth, including the Ring of Flies in the second rectangle of the fourth row, formerly called "Halo of Flies". The name change may have occurred to avoid confusion with Halo of Flies, an item originating from the original Binding of Isaac.

Trivia

• The Black Fly has the lowest health of any enemy in the game, tied with the Corn.
• Eternal Flies were first added to the Wrath of the Lamb DLC for the original Binding of Isaac game.
  • Before Rebirth, Eternal Flies simply became vulnerable and chased the player rather than turning into an Attack Fly.
• There is a variant of Moters in the Eternal Edition of the original The Binding of Isaac that resembles a ball of 4 Attack Flies, or 2 Moters stuck to each other. This enemy does not appear in Rebirth, likely due to being added in said Eternal Edition update that was added a while after the release of Rebirth.
• In a Q&A Reddit thread by Edmund McMillen, Edmund confirmed that the species of flies in The Binding of Isaac are house flies and botflies.
• The Willo originates from the Antibirth mod.
• The name Willo might be a reference to Will'o the Wisps, atmospheric ghost lights seen at night, especially over bogs, swamps or marshes.
• Although Army Flies were known to be revealed during Repentance's first PAX session, it was in fact first revealed in the latest blog of a now-canceled update for the Antibirth mod back in December 21, 2017.

References

The Binding of Isaac: Rebirth
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