Binding of Isaac: Rebirth Wiki

Scolex is a boss that can appear in the Womb Womb and the Added in Afterbirth Scarred Womb Scarred Womb.


Scolex is only vulnerable in his blinking tail segment. He burrows into the ground before performing the following attacks:

  • Jumps out of the ground towards Isaac, burrowing back into the ground at the end of the jump.
    • If Scolex is hit by an explosion while mid-air, he will be deflected backwards.
  • Partially emerges head-first and shoots out a cluster of projectiles towards Isaac, similar to Monstro Monstro, but with a wider spread.
    • After performing this attack, Scolex will always jump out of the same spot he entered.
  • Partially emerges tail-first and fires cluster of 3 red Ipecac Ipecac shots towards Isaac.
    • After performing this attack, Scolex will always jump out of the same spot he entered.

Scolex deals a whole heart of contact damage.

Champion Versions Needs to be unlocked[]

Removed in Repentance Dark Grey: Scolex is 15% larger, slower, and has 25% more HP (375).




  • Scolex appeared in the original The Binding of Isaac.
  • Scolex is the only Boss to have lost access to a Champion variant in an update. Specifically in Repentance, where his dark grey counterpart is inaccessible unless using Console commands to summon it.
  • Scolex can be considered an older or younger version of Pin Pin, but not a posthumous one (that title goes to Added in Afterbirth The Frail The Frail).
  • A scolex is the name of the head of a tapeworm.
  • Compared to the original Binding of Isaac, Scolex's head and tail attacks are swapped.
  • Scolex bears some resemblance to a mythological Mongolian Death Worm, which are described as long, scaly, and blood red. It also raises half its body out of the sand and covers its prey with a lethal acidic substance, which is somewhat similar to Scolex's head attack.


Bug Bug! When Scolex is slowed, some of his body parts may detach or won't even show up - they will only be visible while entering the ground (especially the tail).
Bug Bug! If the final vulnerable segment of Scolex's tail is destroyed using the Chaos Card Chaos Card, the boss will glitch and become harder to kill. The tail will appear again if his head gets bombed or he hits Isaac.
Bug Bug! If you petrify Scolex (with Mom's Contacts Mom's Contacts or other similar items) when it is in mid-air, you can damage any segment of its body.
Bug Bug! If you fire immediately upon entering the Boss Room, rarely, you can damage Scolex before it emerges.
Bug Bug! Added in Afterbirth † If Scolex is under the effects of Broken Modem Broken Modem in mid-air, his jump will be stopped and he will fall.
Bug Bug! If Scolex is frozen with Midas' Touch Midas' Touch or Added in Afterbirth †Dad's Ring Dad's Ring and attacked, he can split into two halves, one with his head and one with his tail.