Blood Skull Gu is an active item in neverbirth, a mod for The Binding of Isaac.

Sacrifices a random eligible familiar belonging to the user and removes one copy of the collectible that granted it.

Gain +1.5 damage and +1 range, and spawn 1-2 full black hearts.

If no eligible familiar is present, take half a red heart of damage instead.

The item still discharges and grants no rewards.

This item contributes towards the Leviathan transformation. Collecting 3 items from this set will grant Isaac flight and +2 Black Hearts.

Blood Skull Gu can be found in the following item pools:

The following tags are applied to this item:

The familiar must be present in the room, owned by the user, and linked to a collectible the user still owns.

Blue flies, blue spiders, wisps, Abyss locusts and summons without an identifiable source collectible are excluded.

The source collectible is removed rather than only dismissing its familiar.

All effects supplied by that lost copy can therefore change.

Each successful sacrifice adds 40 distance units to tear range, equivalent to 1 displayed range.

Stat gains stack and remain after putting Blood Skull Gu down.

Successful sacrifices also leave a red creep effect at the familiar's position.

Backlash can be lethal.

The published version does not save the earned stat bonuses across a full game or mod reload.

• Download neverbirth from the Steam Workshop.