The Acid Trap is one of the key buildables on IX in Call of Duty: Black Ops 4 Zombies. It's required if you're going for the free Death of Orion Wonder Weapon, and it's also useful for clearing large groups of zombies.
Complete Three Arena Challenges
The first part won't appear until you've completed three Podium Challenges.
In the starting Arena, melee one of the hanging challenge banners to begin.
Complete three challenges and once you've finished the third challenge, return to the Challenge Podium in the Arena and collect the Metal Pot (Cauldron).
Find the Chains And Gear
Head underground to the Temple, where Pack-a-Punch is located. Look underneath the balcony on the left-hand side of the Temple. The Chains are hanging from the wall and are always in the same location.
Stay in the Temple and head to the opposite side. Look in the corner near the stairs beneath the hanging skeleton cage. Pick up the Large Gear (Cog). Like the Chains, this part always spawns in the same place.
Build the Acid Trap
Once you have all three parts, head to any one of the four Acid Trap build locations and interact with the skull switch on the wall.
The four build locations are:
- Between the Arena and Ra Tower Entrance
- Between the Arena and Danu Tower Entrance
- On the staircase between Odin Tower Entrance and Odin Altar Room
- On the staircase between Zeus Tower Entrance and Zeus Altar Room
Important: In a normal game, you can only build the Acid Trap at one of these locations. Once it's built, it remains there for the rest of the match.
How to Use the Acid Trap
Stand near the trap and activate it using the interaction button. The trap sprays acid across the floor, quickly melting any zombies caught inside.
The Acid Trap is also used during the Death of Orion quest, where you'll place the Stone Head beneath the trap to melt it and reveal the Scorpion Key.