Dark Arts

Dark Arts is an activated item added in The Binding of Isaac: Repentance. Tainted Judas starts every run with this item.

Effects

When used, Isaac gains +1.0 speed and can walk through enemies/bullets for 1 second or until he shoots. If Isaac walks through an enemy or bullet during this time, it freezes until the effect ends, then takes damage equal to 2x Isaac's damage plus a flat 3.5. At the end of the effect, an area of effect blast is created, dealing more damage the more enemies or bullets were pierced during the effect.
- For every enemy/bullet Isaac walked through, he will gain a temporary +1 damage bonus, which wears off at a rate of -0.25 damage every half second.
- The damage of the blast at the end of Dark Arts is equal to the sum of every damage dealt while dashing between enemies.
  - Bullets walked through will still count for the final blast damage calculation, even though they can't really be damaged.

The duration increases with each use in the same room.
If an enemy Isaac walks through dies before Dark Arts deactivates, they will not give a damage bonus.
Isaac cannot pick up items or donate to Blood Donation machines or Devil Beggars while Dark Arts is activated, but he can pass through Curse Room doors or over spikes and open Mimic Chests without taking damage.
Dark Arts will trigger certain tear effects on enemies it damages, such as burning from Fire Mind.
Dark Arts is extremely effective against enemies with multiple segments such as Larry Jr. because it can affect each segment individually, greatly increasing both the immediate damage and the temporary tear damage bonus.
Invincible enemies such as Stoneys and Stone Grimaces can still be affected and used to increase the damage bonus gained.
Hosts can be damaged and killed even while they are lowered and invincible.

Montezuma's Revenge: The corns created by Montezuma's Revenge can be caught by Dark Arts, and most will naturally, making each cast of Dark Arts give huge boosts of tear damage, and making the final blast deal huge amounts of damage. Not only that, but the Brimstone beam created will still be active while Dark Arts is active.

Bug!	If Tainted Judas or other characters with Schoolbag activate Error: The given collectible ("Glowing Hour Glass") does not exist. right after the use of Dark Arts, they will keep the invincible state but unable to fire and interact with trapdoors (Bombs are allowed) until using Dark Arts again, which works similarly to a movable Gnawed Leaf.