• Antichamber - If the player has [Antibody] , Dark Marker's uncharged shots alternate between firing red and blue charged shots without consuming additional ammo. The shots travel straight and become slow-moving orbs after a short period of time, which can deal multiple instances of damage. If any red and blue shots/orbs touch, the blank effect is activated. The charged shot remains unchanged, and will still consume 10 ammo. If the player has [Backup Gun] and the Antichamber synergy, then shots fired forward will always be blue and shots fired backward will always be red.
• If a player with the Antichamber synergy walks backward and forward in place while shooting normally, it's possible to make the slow-moving orbs collide frequently, causing a large number of blank effects.
• The Antichamber synergy works well with [Double Vision] , as the weapon will always fire one red projectile and one blue projectile at the same time while these projectiles are close to each other, which can cause the blank effect and subsequent explosion to trigger rapidly. If the player also has [Ice Cube] or high Coolness on top of this, the large burst of damage from the rapid explosions from firing Dark Marker while [Double Vision] is active can recharge [Double Vision] almost immediately, allowing the player to almost always have the ability to double their damage output while using Dark Marker.
• In a similar vein, [Scattershot] and [Helix Bullets] make it easier to utilize the blank effect due to putting more bullets on screen. Additionally, [Helix Bullets] make it particularly easy due to it essentially mirroring the behavior of a charged shot and guaranteeing the projectiles will meet.
• Additionally, if the player has [Remote Bullets] alongside the Antichamber synergy, it becomes much easier to have the uncharged red and blue shots collide as the player can manually move them in to one another by rapidly pressing the fire button twice while keeping the cursor in the same location.
• If one wishes to be conservative with their ammo, it is best to empty the magazine using normal shots and then use the charged shot. The charged shot will always empty the current magazine, so using it with one shot left in the magazine is the most efficient use of ammo.
• The blank effect will not reveal secret rooms .
• The blank effect gains bonuses from Ammolets . The [Gold Ammolet] is a particularly good synergy, allowing the effect to clear entire rooms in a single shot.
• The blank effect instantly ignites flammable obstacles (such as cobwebs and oil) and destroys obstacles on the ground in a large radius.
• Unlike most charged weapons, Dark Marker first fires an uncharged shot when the fire button is pressed. This can be avoided by firing while facing against a wall.
• When the gun is [Duct Tape] to another, it adds two separate ammo bars instead of the expected one. Both look identical but one corresponds to the uncharged shot while the other corresponds to the charged shot. Additionally, its mechanics change substantially: instead of firing its uncharged shot semiautomatically, it automatically fires uncharged shots while the charged shot charges in parallel. This generally ends with both the host gun's clip and the uncharged clip emptying while the charged clip remains near-full.
• The uncharged shot fired when the player begins charging the weapon does not anger Bello .
• If the player has the Friend to Gun and Bullet synergy, the secondary Dark Marker will continuously fire charged shots that trigger the blank effect.
• Having items such as [Chaos Bullets] is a negative for this weapon, as the red and blue projectiles often have different bullet speeds.
• If the bullets of a charged shot fail to meet for any reason (due to the effect mentioned above or an NPC 's force field, for example), they will become orbs that pierce and deal multiple instances of damage, trailing off until hitting a wall. These are identical to the uncharged shot of the Antichamber synergy.
• The charged shot of this weapon can damage Cannonbalrog during his teleporting attack.

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