Binding of Isaac: Rebirth Wiki

After obtaining 3 fly items from the following list (Added in Repentance 3 items with the fly item tag), Isaac turns into a giant humanoid fly and gains flight. While in this form, most types of enemy flies will automatically be converted into Blue Flies. Added in Repentance Enemies such as Boom Fly Boom Flies and its variants will become friendly and be brought with Isaac to other rooms and floors.

Active Collectibles[]

Name ID Icon Quote Description Added in Repentance Quality
Added in Afterbirth Jar of Flies 5.100.434
Jar of Flies
Bug catcher Killing an enemy adds a fly to the jar, up to a maximum of 20. On use, releases Blue Flies equal to the number of flies in the jar. 2
Added in Repentance Plum Flute 5.100.650
Plum Flute
4 rooms
Play time! Summons the boss Added in Repentance Baby Plum Baby Plum to fight for Isaac in the current room. 2

Passive Collectibles[]

Name ID Icon Quote Description Added in Repentance Quality
???'s Only Friend 5.100.320 ???'s Only Friend Controlled friend Spawns a controllable familiar that deals 37.5 damage per second on touch. It can be moved using the shooting directional keys 2
BBF 5.100.272 BBF Big Beautiful Fly Spawns a familiar that flies around the room in a zig-zag pattern and explodes on contact with an enemy. Respawns after ten seconds. 1
Best Bud 5.100.274 Best Bud Sworn protector When hit, spawns a quickly orbiting attack fly similar to Forever Alone Forever Alone for the current room that deals high damage. 0
Big Fan 5.100.279 Big Fan Fat protector Spawns a large orbital familiar that blocks enemy shots and deals 30 damage per second to enemies. 2
Distant Admiration 5.100.57 Distant Admiration Attack fly Spawns an attack fly that circles further out than Halo of Flies Halo of Flies, but closer than Forever Alone Forever Alone, dealing 75 damage per second. 2
Forever Alone 5.100.128 Forever Alone Attack fly Spawns an attack fly that orbits a long distance from Isaac, dealing 30 damage per second. 1
Halo of Flies 5.100.10 Halo of Flies Projectile protection Spawns two Pretty Flies that block enemy shots and deal contact damage to flies. 2
Hive Mind 5.100.248 Hive Mind Giant spiders and flies Increases the size of Blue Spiders and Blue Flies and doubles the amount of damage they deal. Added in Repentance Also increases the effectiveness of fly and spider familiars. 2
Skatole 5.100.9 Skatole Fly love Flies become harmless or less dangerous depending on the type. 0
Smart Fly 5.100.264 Smart Fly Revenge fly Spawns an orbital familiar that blocks enemy shots. Upon taking damage, the familiar will pursue enemies for the rest of the room, dealing 22.5 damage per second. 2
The Mulligan 5.100.151 The Mulligan They grow inside Tears have a 1/6 chance of spawning allied Blue Flies when they hit an enemy. 3
Added in Afterbirth Friend Zone 5.100.364 Friend Zone Friendly fly Spawns a white attack fly that orbits somewhere between Distant Admiration Distant Admiration and Forever Alone Forever Alone, dealing 45 damage per second. 1
Added in Afterbirth Lost Fly 5.100.365 Lost Fly Lost protector Removed in Repentance Spawns fly familiar that moves in a straight line and circles around the first wall or obstacle it hits, dealing 105 damage per second on contact.
Added in Repentance Spawns fly familiar that moves in a straight line and circles around the first wall or obstacle it hits, dealing 56 damage per second and forcing nearby enemies to attack it.
Added in Afterbirth Obsessed Fan 5.100.426 Obsessed Fan Follows my every move... Spawns a familiar that follows Isaac's movements on a delay and deals 30 contact damage per second to enemies. 0
Added in Afterbirth Papa Fly 5.100.430 Papa Fly Turret follower Spawns a familiar that follows Isaac's movements on a 3 second delay, firing tears at nearby enemies. 1
Added in Afterbirth † Angry Fly 5.100.511 Angry Fly He's violent Spawns a fly familiar that orbits around a random enemy and deals 30 damage per second to enemies it comes in contact with. 1
Added in Repentance Bot Fly 5.100.629 Bot Fly Defense drone Spawns an orbiting fly familiar that fires shielded tears at incoming enemy projectiles. 3
Added in Repentance Fruity Plum 5.100.649 Fruity Plum Bouncy friend Gives Isaac a miniature Baby Plum Baby Plum familiar that propels itself diagonally around the room, firing tears behind itself as it travels. 1
Added in Repentance Parasitoid 5.100.461 Parasitoid Egg tears! Adds a chance to fire an egg sack which creates slowing creep and spawns a Blue Fly or Blue Spider upon hitting an enemy. 3
Added in Repentance Psy Fly 5.100.581 Psy Fly Flamboyant protector Spawns a fly orbital familiar that chases and deflects enemy shots and converts them into homing tears that deal 2 damage. Turns some Fly enemies into friendly Blue Flies if it touches them while deflecting shots. 4
Added in Repentance The Swarm 5.100.693 The Swarm Infest Spawns eight orbital flies, which turn into Blue Flies after they block a shot. Each time a room is cleared, spawns another orbital fly. 2
Added in Repentance YO LISTEN! 5.100.492 YO LISTEN! Yo listen! +1 luck. Spawns a fairy familiar that points out Secret Room Secret Rooms, Crawl Space Crawl Space entrances, and tinted rocks. 2


  • Isaac starts with this transformation in the Solar System challenge.

Unlockable Achievements[]

  • Lord of the Flies
    Lord of the Flies - Become Beelzebub.


  • Beelzebub, also known by "Lord of the Flies" and many other names, is known as one of the 7 princes of hell. Beelzebub is also another name for the devil.
  • In modern Catholic tradition, Beelzebub is regarded as one of the 7 princes of Hell; however, the origins of the name Beelzebub actually dates back to an early Jewish insult for worshippers of a Canaanite Deity Ba'al 'Lord', or Ba'al-Zvul 'Lord of the manor/dwelling', calling him Ba'al-Zvuv, 'Lord of the flies'.
    • The achievement 'Lord of the Flies' is a reference to this.


PC W2DW TA79 (Allows Isaac to become Beelzebub in The Caves XL. First two Treasure Rooms are Big Fan and Attack Fly, one of the Treasure Rooms in Caves XL is Halo of Flies)

PC 9CM4 JDBL (Last fly item collected on Flooded Caves I)

PC B14A Q44Y (Also contains four Guppy items)

Switch TF11 R19Z (First three floors Treasure Rooms contain Smart Fly, Forever Alone, and Infestation)