Lost Fly
ItemAfterbirthUnlocked
familiarGame ID 365★★★★
How do you unlock Lost Fly?
Verified starting unlockSource data confirms that no unlock is required.
Spawns a fly familiar that moves in a straight line and circles around the first wall or obstacle it hits. [Before Repentance] It deals 105 damage per second on contact. [Repentance] It deals 56 damage per second and forces nearby enemies to attack it.
Available from the start
No unlock needed — this is available in every new save file.
What unlocking Lost Fly leads to
Nothing depends on this yet.
Source: bindingofisaacrebirth.wiki.gg
Imported 2026-09-13