Fetus in a Jar is a passive item in Sacred Dreams, a mod for The Binding of Isaac.
Spawns an orbital familiar which blocks shots and deals contact damage.
The familiar can be upgraded up to 3 times by obtaining additional Fetuses In a Jar. Each level has its own characteristics.
Level 1: Blocks projectiles and deals 3 damage on contact.
Level 2: Transforms from an orbital to a follower that shoots piercing buzzsaws at nearby enemies.
The buzzsaws can break obstacles.
Level 3: Increases the size of Doctor Fetus. Now shoots homing rockets instead of buzzsaws.
Obtaining additional Fetuses In a Jar will create a new level 1 fetus and start the cycle again.
Can drop after defeating a Harbinger.