| One time use|
|(page 5, column 11, line 3)
| Take 50 devil dealsSacrificial Altar|
Sacrificial Altar is an unlockable activated item added in Booster Pack #5.
- Upon use, sacrifices up to 2 familiars and spawns an item from the Devil Room Pool for each familiar sacrificed.
- The order in which the familiars were obtained does not matter; it picks 2 at random to sacrifice.
- If Isaac has no familiars, the item will do nothing and will not be consumed.
- If the Devil Room Pool has no items left, one or two copies of PentagramIncreases damage and increases the chance for a Devil or Angel Room to appear. are spawned.
- When playing Greed Mode the normal Devil Room Pool is still used, instead of the Greed Mode pool.
- In addition to the familiars, any blue flies or spiders will be converted to 1 coin each.
- If playing as Lilith, the IncubusA demonic familiar that follows Isaac and shoots tears identical to Isaac's in terms of damage, range, fire rate, and effects. familiar will not be sacrificed.
- Charmed enemies cannot be sacrificed, even if permanently charmed.
- Any pretty flies are counted as a single sacrifice.
- Best BudWhen hit, summons a white attack fly similar to Distant Admiration for the current room. / Dead BirdSpawns a flying familiar for the current room that chases enemies whenever Isaac takes damage. / Eve's Bird Foot5% chance to spawn a Dead Bird familiar for the current room each time an enemy dies.: These familiars can be sacrificed only when they're active.
- Box of FriendsUpon use, duplicates all of Isaac's familiars for the current room.: The familiars generated by Box of Friends can be sacrificed and turned into items.
- Car BatteryCauses Isaac's activated item to activate twice on each use.: No effect; only spawns one item per familiar sacrificed, and can only sacrifice up to 2 familiars.
- ChaosChaos causes items to be chosen from random item pools. When picked up, drops between 1-6 random pickups on the floor.: The Altar ignores the effects of Chaos, always spawning items from the Devil Room Pool instead of a random pool.
- Guardian AngelSpawns an orbital familiar that blocks enemy projectiles, deals contact damage to enemies, and increases the speed of all orbital familiars. / SeraphimAn angel familiar which follows Isaac and fires homing tears which deal 10 damage at -25% shot speed and a reduced fire rate. / Sworn ProtectorAn orbital angel which does 7 contact damage per tick and blocks enemy shots. Upon blocking 10 shots in a room it drops an eternal heart.: 2 black hearts will also drop.
- Lil DeliriumGrants a familiar that transforms into another random familiar every 10 seconds.: Lil Delirium may be sacrificed, but the item is not removed. The familiar will return once another familiar is gained or lost, or the run is quit and resumed.
- More OptionsTwo items spawn in every Treasure Room. Only one can be taken; the other will disappear./ There's OptionsThere will be 2 items available to choose from after defeating a boss. Choosing 1 item causes the other to disappear.: Sacrificial Altar ignores the effect of these items.
- VoidConsumes all pedestal items in the room. Active items will have their effects added to Void, and passive items will grant stat upgrades.: When absorbed by Void, the one time use no longer applies unlike other one time use active items. Familiars can be sacrificed with every activation of Void.
- ZodiacZodiac will give Isaac a random zodiac item effect that changes after every floor.: A Gemini familiar granted by Zodiac can be sacrificed without losing the item.
- The following familiars, followers, and orbitals cannot be sacrificed:
- 1up!Gives an extra life. Upon death, you will respawn in the previous room with full health and lose the 1up!.
- 7 SealsGrants a random Harbinger familiar that changes every 10 seconds.
- Angelic PrismGrants a prism orbital with a large orbital radius. Tears that pass through the prism split into four multi-colored tears.
- Angry FlySpawns a fly familiar that orbits around a random enemy and deals 5 damage per tick to enemies it comes in contact with.
- Bomb BagIsaac is followed by a small bag that drops a Bomb, 1+1 Free, or a Troll Bomb every 3 rooms.
- CenserGives Isaac a golden censer familiar which creates a huge aura of light that slows down any enemies and enemy shots inside it.
- Daddy LonglegsDaddy Long Legs' shadow follows Isaac and stomps on enemies.
- Dead CatSets the amount of red heart containers to 1, but gives Isaac 9 extra lives. After dying, Isaac is teleported to the last safe room. New heart containers can be obtained after picking up this item, but after each death, the number of heart containers is set to 1 again.
- DepressionSpawns a cloud familiar that leaves a trail of tears that damages enemies. Has a chance to spawn damaging beams of light onto enemies that touch the cloud.
- Finger!Spawns a finger familiar that points at enemies, dealing constant damage.
- GB BugA glitch familiar that bounces around the room and applies a random status effect to any enemies it comes into contact with and has a chance to re-roll pickups that it passes over.
- GuillotineIsaac's head is removed from his body and floats around him. Increases Damage by 1 and grants -1 Tear Delay.
- Guppy's Hair BallLoosely follows behind Isaac. Can be swung like a flail by rapidly spinning Isaac in a circle. Grows bigger by killing enemies.
- Hallowed GroundSpawns a white poop familiar, which turns into a white poop when Isaac is hurt.
- Holy WaterWhen Isaac receives damage, the bottle breaks and a puddle of blue creep forms, which damages non-flying enemies, similar to Lemon Mishap. The bottle is reformed upon entering a different room.
- Jaw BoneSpawns a familiar that flies the room while firing, dealing double Isaac's tear damage to enemies that come in contact and retrieving pickups.
- Juicy SackA familiar that follows behind Isaac. It drips a trail of creep, which slows enemies, and spawns 1-2 blue spiders after each room.
- Key Piece 1Combined with Key Piece 2, unlocks the golden gate in the starting room of The Chest and Dark Room to fight Mega Satan. and Key Piece 2Combined with Key Piece 1, unlocks the golden gate in the starting room of The Chest and Dark Room to fight Mega Satan.
- Milk!A glass of milk follows Isaac and spills on the floor upon taking damage. After the milk spills, Isaac's tear delay is decreased by 2 for the rest of the room.
- Mom's RazorSpawns an orbiting razor that damages enemies it touches and inflicts bleeding on enemies, causing them to slowly take damage over time.
- Mom's ToenailMom's foot randomly stomps down somewhere in the room. 1 minute intervals.
- Mystery EggSpawns an egg familiar, which cracks and turns into a random charmed enemy when Isaac is hurt. The egg regenerates upon entering a different room.
- Mystery SackSpawns a familiar that follows Isaac around and has a chance to drop a heart, coin, bomb, or key after clearing a room.
- Pointy RibSpawns a bone familiar that can be aimed with the fire buttons and does contact damage.
- The RelicIsaac is followed by a small blue cross that will drop a Soul Heart every 4 rooms.
- Rune BagA bag that follows Isaac and drops a random rune every 3 rooms.
- Sack of PenniesIsaac is followed by a small bag that drops a coin every 2 rooms.
- Sack of SacksSpawns a sack familiar that has a chance to drop a sack upon clearing a room.
- Sacrificial DaggerDagger orbits Isaac, dealing very high damage.
- Samson's ChainsPull a chain and ball behind you that will damage enemies on contact and is able to break stones.
- Slipped RibSpawns a bone familiar that circles around Isaac and reflects enemy shots.
- TonsilWhen hit, there is a small chance a removed tonsil familiar starts following Isaac, blocking enemy shots.
- Umbilical CordWhen Isaac's health is brought to half a red heart and no soul hearts, a Little Steven familiar spawns for the current room.