Eraser

Effects

On use, Isaac holds an Eraser above his head, which can be thrown in any cardinal direction. Upon hitting a monster, the monster will be "erased", preventing it from appearing for the rest of the run.
- Deals 15 damage to bosses. If fatal, erases the boss for the rest of the run.
Can only be recharged by entering a new floor. Batteries and most other methods of recharging have no effect.

Erased enemies and bosses appear as a brief pink puff of smoke. Any on-death effects are not checked.
- The Seven Deadly Sins minibosses and Angels will still drop their respective pickups or items.
- If used on multistage bosses like Hush or Ultra Greed, erasing the first phase skips any further phases.
Has no effect on invincible enemies, such as (Stone Grimace) Stone Grimaces, lowered (Host) Hosts, or (Eternal Fly) Eternal Flys.
(Bulb) Bulbs can steal charges from the Eraser.
Erased enemies and bosses will remain erased if a Victory Lap is started.
- Erased enemies and bosses will also remain erased if items such as R Key or Genesis are used.
Entities such as Ultra Greed Coins or Little Horn's (Dark Ball) Dark Balls are considered enemies and can be erased.
It is possible to erase (Charger) Chargers, rendering (Chubber) Chubbers unable to attack.
Erasing (Polty) Poltys will render (Haunted Chest) Haunted Chests harmless, but may make some rooms impossible to complete without bombs or flight as they rely on a Polty clearing a path.
Each floor traveled up during the Ascent will recharge the Eraser.

Angelic Prism: Throwing the Eraser through the Angelic Prism will cause it to split into four.
The Battery: The eraser can gain an extra charge if it is not used on one floor.
(Bethany) Bethany / (Tainted Bethany) Tainted Bethany: Soul and blood charges can be used with the Eraser, allowing multiple uses per floor.
Blood Puppy: Throwing the Eraser at an enraged Blood Puppy (second stage) will 'erase' its enraged form, keeping it permanently tame.
- Throwing the Eraser at its third stage will make it cycle through its normal and second stage as it kills enemies.
Book of Virtues: Spawns a pink eraser wisp on the middle ring. The wisp is immune to projectiles. If a non-boss enemy touches the wisp, it is erased and the wisp is destroyed. The wisp cannot erase bosses, regardless of how much health they have left.
Glowing Hour Glass: Using Glowing Hour Glass to return to the previous floor will keep the charge Eraser received from entering the next floor.
Void: An eraser can be thrown with each use of Void after absorbing it, allowing multiple uses per floor.

9 Volt / Battery Pack: Item doesn't fully charge the Eraser when picked up.
Book of the Dead / Friend Finder / Mystery Egg / Poke Go / (Polished Bone) Polished Bone: Enemies spawned by these items will not spawn if that type was erased, potentially rendering them useless.
My Shadow: Erasing a (Charger) Charger will prevent all newly created friendly Chargers from spawning, rendering the item useless. The item spawns a normal Charger before changing it to the special My Shadow variant.
Number One: Lowers the Eraser's range drastically, making the item much more difficult to use. Range increases do not negate this.
Sharp Plug: Attempting to recharge the Eraser with the Sharp Plug hurts Isaac for half a heart without recharging the item.