Gives Isaac a spider familiar that burrows in Isaac's head, firing four slowing tears in addition to Isaac's normal tears.
The slowing tears deal 1.5 damage each, and are fired at a rate of once every 1.5 seconds.
These tears are unaffected by Isaac's damage and tears stats; they have fixed damage and fire rate.
Upon taking damage, there is a chance that Isaac's head will pop, spawning friendly spiders, and release the Intruder familiar, who will leap at enemies to deal contact damage, and fires four slowing tears towards nearby enemies instead of Isaac.
The spider familiar deals up to 4.5 contact damage depending on how fast it's moving and fires slowing tears twice as fast compared to when it's in Isaac's head.
The chance for activation goes up to 100% at 4 luck.
The familiar lasts for the current room, and Isaac's head is reattached upon entering a new room.
This item belongs to the Spider Baby set. Collecting three items from this set will transform Isaac into a humanoid spider.
The Intruder is treated as a familiar even while in Isaac's head, and benefits from familiar synergies while in it.
If The Intruder is released after The Pinking Shears are used, control is given back to an invisible head with only a shadow visible. This is due to both the head (the spider) and the body being mobilized to attack.
Box of Friends: Doubles the number of tears fired from Isaac's head (if both copies fire at the same time, the tears will stack perfectly so it can be difficult to tell). If The Intruder is released, then interacts normally and spawns a copy.
Hive Mind: Increases The Intruder's tear and contact damage.
Lilith: The Intruder's tears come from Lilith, despite her blindfold.