Jaw Bone

Treasure Room Treasure Room Greed

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Jaw Bone is an unlockable passive item added in Booster Pack #5.

Effects

• Spawns a familiar that flies around the room while firing, dealing double Isaac's tear damage to enemies that come in contact.
  • When thrown, the familiar will pierce through enemies if they are killed by the familiar, but the familiar will bounce back to Isaac if the enemy is not killed.
  • The familiar can retrieve pickups like The BoomerangThrows a short-range boomerang which does a bit of damage and has a high chance to stun the enemy for 2 seconds. Can also be used to grab pickups..
  • Blocks enemy tears when stationary and when thrown.

Synergies

• BFFS!Increases the size and damage of familiars.: Familiar grows in size and does quadruple Isaac's tear damage to enemies.
• Duct TapeStops Isaac's familiars from moving.: Jaw Bone will face in the same direction as Isaac and remain stationary as opposed to trailing behind him. Jaw Bone can still be fired.

Trivia

• This item is possibly a reference to Judges 15:16 where Samson kills a thousand men with a donkey's jaw bone.
• Possibly a reference to the movie, The Frighteners, where Judge chases a ghost hound who keeps stealing his jaw bone.

Bones

Items:

• Brittle BonesReplaces all red hearts with 6 empty bone hearts. Upon losing a bone heart, Isaac fires bones in 8 directions and permanently gains a tears up.
• Compound FractureIncreases range. Tears turn into bones, which shatter into 1-3 bone shards upon hitting an enemy or obstacle.
• Dead ToothWhile firing, Isaac gains a green aura that poisons nearby enemies.
• Dog ToothIncreases damage and speed. Upon entering a room adjacent to a secret room, a howl sound effect will play.
• 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.
• MarrowGrants one bone heart and spawns three red heart pickups.
• Monstro's ToothMonstro jumps onto a random enemy, doing area damage. Can damage/kill the player if summoned in an room without enemies.
• My Little UnicornUpon use, grants invulnerability and increased speed for five seconds, removing the ability to shoot tears and replacing it with the ability to deal contact damage to enemies.
• Pointy RibSpawns a bone familiar that can be aimed with the fire buttons and does contact damage.
• Slipped RibSpawns a bone familiar that circles around Isaac and reflects enemy shots.
• Unicorn StumpUpon use, grants invulnerability and increased speed for five seconds, but removes the ability to shoot tears.

Trinkets:

• Black ToothAdds a chance to fire a black tooth that poisons enemies.
• Cursed SkullIf Isaac has less than one full red heart after taking damage, he will be immediately teleported to the last cleared room he was in.
• Finger BoneGrants a chance to gain a bone heart upon taking damage.
• Rib of GreedPrevents Greed and Super Greed from appearing in Shops and Secret Rooms.
• Wish BoneTaking damage has a small chance to destroy the trinket and spawn a random item.

The Forgotten Unlocks
|-	Marrow		Unlocked a new item.	Defeat Mom's Heart or It Lives! on hard mode as The Forgotten	392
Slipped Rib		Unlocked a new item.	Defeat Isaac as The Forgotten	393
Pointy Rib		Unlocked a new item.	Defeat Satan as The Forgotten	394
Jaw Bone		Unlocked a new item.	Defeat ??? as The Forgotten	395
Brittle Bones		Unlocked a new item.	Defeat The Lamb as The Forgotten	396
Divorce Papers		Unlocked a new item.	Complete the Boss Rush as The Forgotten	397
Hallowed Ground		Unlocked a new item.	Defeat Hush as The Forgotten	398
Finger Bone		Unlocked a new item.	Defeat Ultra Greed as The Forgotten	399
Dad's Ring		Unlocked a new item.	Defeat Ultra Greedier as The Forgotten	400
Book of the Dead		Unlocked a new item.	Defeat Delirium as The Forgotten	401
Bone Baby		Unlocked a new co-player baby.	Earn all Hard Mode Completion Marks as The Forgotten	402
Bound Baby		Unlocked a new co-player baby.	Defeat Mega Satan as The Forgotten	403

Booster Packs
#1	Angry FlySpawns a fly familiar that orbits around a random enemy and deals 5 damage per tick to enemies it comes in contact with. Black HoleThrows a black hole on the ground which sucks in and damages enemies. BozoIncreases damage by a flat 0.1 and grants a soul heart. Enemies can randomly become briefly charmed or feared. Taking damage has a chance to spawn a rainbow poop. Broken ModemEnemies, enemy shots, tears, and pickups will briefly freeze in place at random intervals. Mystery GiftUpon use, spawns a random item from the current room's item pool, with a chance to spawn A Lump of Coal or The Poop instead. SprinklerUpon use, spawns a sprinkler that rotates and fires tears. Fast BombsGrants 7 bombs and allows bombs to be placed rapidly. Buddy in a BoxGrants a familiar with a random tear effect. The familiar is randomized at the start of each floor. Lil DeliriumGrants a familiar that transforms into another random familiar every 10 seconds. HairpinFully recharges Isaac's active item upon entering a boss fight. Wooden CrossGrants a Holy Mantle shield upon entering a new floor, which protects against one hit of damage. Butter!Using an active item will drop it onto a pedestal on the ground. Taking damage may result in dropping a passive item. Huge GrowthMakes Isaac large for the current room, increasing his range and damage. Ancient RecallSpawns 3 random cards. Era WalkFor the current room, enemies are slowed, Isaac's speed is increased, and his shot speed is decreased.
#2	Jumper CablesGrants an active item charge every 15 enemies killed. CouponUpon use, makes a random item from a shop, devil deal, or black market free. TelekinesisUpon use, for the next two seconds, any enemy shots that come near Isaac are held in place. After the charge is depleted, they are fired back as tears. Moving BoxIf the box is empty, picks up all items and pickups in a room and stores them. If the box is not empty, places all stored items and pickups in the current room. Technology ZeroConnects Isaac's tears with electricity that can damage enemies. LeprosyUpon taking damage, grants a body part as an orbital, which blocks enemy shots and deals 7 damage per tick to enemies it comes in contact with. The orbitals will be destroyed if they take enough damage from enemies or enemy shots. Filigree FeatherAngels drop items instead of key pieces when defeated.
#3	7 SealsGrants a random Harbinger familiar that changes every 10 seconds. Mr. ME!Summons a controllable ghost that can perform various tasks depending on what it targets. Angelic PrismGrants a prism orbital with a large orbital radius. Tears that pass through the prism split into four multi-colored tears. Pop!Replaces Isaac's tears with eyeballs that can bounce off of each other. The eyeballs are not limited by range, and will instead dissipate when they stop moving or when hitting an enemy or obstacle. Door StopThe last door Isaac went through stays open, allowing him to leave the room even if enemies are in it.
#4	Death's ListGrants a reward if all enemies in a room are killed in the order they are marked. HaemolacriaTears are now fired in an arc. Upon hitting the floor, an obstacle, or an enemy, they burst into many smaller tears in all directions. Increases tear delay. LachryphagyIsaac's tears decelerate as they travel. Upon stopping or hitting an obstacle, they burst into 8 tears in all directions. Tears can be fired into other tears to feed them, increasing their damage. TrisagionTears are replaced with piercing white blasts of light. SchoolbagAllows Isaac to hold two active items. Extension CordBeams of yellow electricity flow between Isaac and his familiars, damaging any enemies between them.
#5	BlanketGrants one soul heart. Upon entering a boss room, grants a shield that blocks one hit, then disappears. Sacrificial AltarUpon use, sacrifices up to 2 familiars and spawns an item from the Devil Room Pool for each familiar sacrificed. Lil SpewerSpawns a random pill, and grants a small Spewer familiar that charges up and fires different types of creep. MarblesSpawns 3 random trinkets. Taking damage has a small chance to swallow Isaac's currently held trinket, gaining its effect permanently. 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. Flat StoneTears bounce off the floor. Tears that hit an enemy after bouncing deal splash damage to all nearby enemies for 25% of Isaac's tear damage. MarrowGrants one bone heart and spawns three red heart pickups. Slipped RibSpawns a bone familiar that circles around Isaac and reflects enemy shots. Hallowed GroundSpawns a white poop familiar, which turns into a white poop when Isaac is hurt. Pointy RibSpawns a bone familiar that can be aimed with the fire buttons and does contact damage. Book of the DeadUpon use, spawns a charmed Bony or an orbital bone for each enemy killed in the current room. Dad's RingCreates a ring of light around Isaac that petrifies enemies in contact. Divorce PapersSpawns a Mysterious Paper, increases tears, and grants a bone heart. 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. Brittle BonesReplaces all red hearts with 6 empty bone hearts. Upon losing a bone heart, Isaac fires bones in 8 directions and permanently gains a tears up. Broken ShovelWhile held, causes multiple Mom's Foots to come down and stomp on Isaac. One of two parts necessary to create Mom's Shovel. Broken ShovelOne of two parts necessary to create Mom's Shovel. Mom's ShovelSpawns a trapdoor that leads to the next floor upon activation. Unlocks The Forgotten when used on a mound of dirt that appears in The Dark Room. Rotten PennySpawns a blue fly every time a coin is picked up. Baby-BenderGrants Isaac's familiars homing shots. Finger BoneGrants a chance to gain a bone heart upon taking damage.