|An infernal barrier preventing passage to the Forge.
After the first Gungeoneer surmounted the Hollow, powerful Gunjurers shaped the Wallmonger from the shells of hundreds of discharged Gundead.
Wallmonger spans the entire width of the room, with its "face" in the center. It continually moves downwards, and if it is not killed by the time it reaches the end of the room, the player will be instantly killed. Wallmonger has a variety of attacks:
- Spits a trail of fire down the center of the room, followed by firing large blocks of bullets down each side while also firing spreads of bullets.
- Fires alternating spreads of bullets that widen as they travel down the room.
- Fires expanding rectangular formations of bullets.
- Fires a line of waving bullets that spans the width of the room.
- The large blocks of bullets that are fired when there is fire in the middle of the room can be avoided by dodging right through them.
- Items that grant the player flight and items that grant fire immunity make the fight a bit easier, as the fire trail actually becomes a safe space.
- Mega Douser can extinguish the flames in the center, making the fight slightly easier.
- Bug Boots can replace the flames with poison to similar effect.
- Beware of dropping items during the boss fight, as they can become inaccessible afterwards due to Wallmonger moving and dying on top of the items. This is especially important when carrying the Busted Television.
- If you have Bloodied Scarf or Ring of Ethereal Form, you can get to the area behind Wallmonger. It is completely safe there, but you cannot see your character. The camera follows Wallmonger, which moves constantly, so downward movement may be required to get back in range.
- If you have Live Ammo or any other item that prevents contact damage, the Wallmonger will still deal contact damage.
- Wallmonger can be slowed with items such as Triple Crossbow.
- Wallmonger can be stopped from moving by placing Portable Turret, which can also stop bullets.
- Wallmonger can be stopped with enough knockback, Disintegrator with Weird Science synergy provides 210 knock-back which is enough to cause Wallmonger to stop in place. If stopped in this way, it will barely shoot, making the fight very easy.
- Wallmonger can be stopped from moving if a chicken is placed infront of the boss. This won't stay for long since the chicken can be killed by the bullets from the boss.
- In order to do this, you must have Lament Configurum, a weapon that turns enemies to chickens, and have the wall coming toward you. You must have the Lament Configurum to activate and an enemy to appear in front of the wall. You must turn the enemy to a chicken before it gets left behind the wall or dies. If you're lucky and successful, the chicken would stop at the wall, giving you an advantage since bullets would take longer to hit you, the lava trial attack being much easier, and the wall being stuck. Note that your guns must be able to reach the wall since the camera would still go down. If you don't have a gun to reach the wall, you would have to die or be stuck in a softlock.
- A softlock can occur if a freezing weapon such as the Crestfaller is used to kill Wallmonger; its death animation will be drastically slowed, and the player will not be able to move after it finishes.
- The item pedestal that spawns after defeating Wallmonger cannot be a Mimic, even if the player has the Mimic Tooth Necklace, because the pedestal spawns too close to Wallmonger.
- If receiving an item from a pedestal and the maximum number of items is already held, it is possible for the dropped item to bounce down under the dead wall, making it impossible to retrieve again.
- The Wallmonger may have several influences:
- One such source of inspiration is the Wall of Flesh from Terraria, who needed to be killed before it forced you to the edge of the world. Backing this up is the fact that there seems to be corpses inside the wall.
- Another possible inspiration is the Demon Wall bosses from Final Fantasy.
- Or the Living Wall from Advanced Dungeons & Dragons 2nd edition.
- Or Wall Face/Doom's Wall in Secret Of Mana.
- Or The Nuclear Throne enemy, from the game of the same name.
- Or the Source Wall of DC Comics, given the embedded Gundead within it.
- Or the wall of dead soldiers built in the movie 300
- The Wallmonger's fight can only be accessed if the boss room door is on the left or the right, because Wallmonger only moves forward.
- The name Wallmonger is a portmanteau of wall and warmonger.
- The Wallmonger's Ammonomicon picture and boss into sprite are very different with the intro sprite having only bullet & shotgun kin, while the Ammonomicon entry has every detail on the in-game sprite.