Blood Bombs is a passive item added in The Binding of Isaac: Repentance.
- Gives Isaac a heart container and heals him for five hearts.
- Causes Isaac's bombs to leave a pool of red creep on the ground when they explode.
- The creep deals 2 damage per tick (20 per second) and lasts ~15 seconds.
- If Isaac has no bombs, allows him to place a bomb at the cost of taking half a heart of damage. This prioritizes red hearts over soul hearts.
- Placing a bomb using health counts as self-damage, and as such, does not affect the chances for a Devil deal, nor does it trigger Damocles.
- Keeper will take 1 Coin Heart of damage in exchange for 1 bomb.
- Placing a bomb which costs half a heart of damage will prioritize red hearts first.
- Therefore, you can remain at zero bombs and leave excess drops of bombs and hearts to maximize your resource use for the floor.
- This mechanic can be used to enter a Curse room without taking blue/black heart damage.
- But be careful and remember to move quickly upon exiting the Curse room if you used this mechanic to enter, otherwise you'll take the explosion damage.
- This is the only bomb-augmenting item that does not give any bombs on pickup.
- The fact that the item gives a heart container and healing instead of bombs may be a hint for the mechanic of using health for bombs, as well as a substitute for actual bombs.
- The fact that the item gives a heart container and heals up to exactly 5 containers, along with the appearance, makes it very similar to Blood Bag.
- A Blood Donation Machine will be shown as a cause of death on Isaac's last will if he dies as a result of placing a bomb and losing all health.