Bird Cage

Bird Cage is a passive item added in The Binding of Isaac: Repentance.

Effects

 * Gives Isaac a fat bird familiar that sits on Isaac's head until he takes damage.
 * Upon taking damage, it will jump off of Isaac's head and land on the nearest enemy, dealing damage and creating a rock line in a random direction. For the rest of the room, it acts like, flying around, albeit slower, and dealing contact damage to enemies.
 * Bird Cage does 45 damage to enemies it lands on and 10 damage per rock wave that hits enemies, then does 3 contact damage per tick while chasing enemies (9 damage per second). The rock waves can destroy obstacles.

Synergies

 * : Spawns 4 rock waves in an X pattern and doubles contact damage. Damage of the jump and the rock waves is unaffected.
 * : Can be used after the familiar has jumped.
 * : Boosts the familiar's damage while spinning, although has no effect on its speed.

Interactions

 * : Multiple copies of the item provide no benefit and won't make more than one familiar appear.
 * : Immediatelly makes the familiar jump, leaving a ghost copy on Isaac's head until he takes damage. This has no benefit to the damage dealt and will not spawn more than one familiar.

Trivia

 * The item's name is a pun: the familiar resembles the Cage boss, and it functions like Dead Bird, thus making it a "Bird" version of the Cage.