What to know

  • The Rainbow Vomit is a Jakobs Legendary shotgun that shoots multiple elemental pellets, each shot applying multiple effects.
  • To unlock the boss who drops it, you must complete a five-part side mission chain starting in Carcadia Burn.
  • The boss, Leader Willem, can be farmed repeatedly using Moxxi’s Big Encore machine for guaranteed farming.
  • Alternative ways to obtain the weapon include legendary vending machines and a Wildcard mission reward after finishing the main story.

The Rainbow Vomit shotgun in Borderlands 4 stands out due to its colorful elemental projectiles and ricochet mechanic on critical hits. It is a highly sought-after weapon for players who want a versatile elemental shotgun that doesn’t require constant weapon swapping.

Rainbow Vomit shotgun location: Where to find and farm it

The primary reliable method to obtain the Rainbow Vomit is by farming Leader Willem, a special boss in Carcadia Burn. This boss only becomes available after completing a chain of five side missions starting from Carcadia City:

  • Enter the Electi Part 1
  • Enter the Electi Part 2
  • The Council Divided
  • Traitor Within
  • The Mole’s Gambit (final mission where you fight Leader Willem)

Leader Willem is located to the east of Grindstone of the Worthy in Carcadia Burn, near The Excrucible and the path to Terminus Range. After defeating him once in the mission, you can respawn him indefinitely by paying a small fee at Moxxi’s Big Encore machine placed nearby.

A small tip for farming location and travel

The easiest way to reach Leader Willem’s arena is by starting from the nearby silo called Rustic Hurl. Jumping from the silo and using a ripcord can save time by climbing up the cliffs quickly instead of walking around.

Step-by-step guide to farming the Rainbow Vomit shotgun

Step 1: Reach Carcadia City in Carcadia Burn

Travel to the faction settlement Carcadia City, which serves as the hub for the side mission chain to unlock Leader Willem.

Step 2: Accept and complete the side mission chain

Start from Levaine in Carcadia City and complete the quests in this order: Enter the Electi Part 1, Enter the Electi Part 2, The Council Divided, Traitor Within, and finally The Mole’s Gambit.

Step 3: Defeat Leader Willem in The Mole’s Gambit

At the end of the last mission, you will face Leader Willem. Defeat him to receive loot with a chance to get the Rainbow Vomit.

Step 4: Use Moxxi’s Big Encore to respawn Leader Willem

After completing the mission, you can farm him repeatedly by paying a fee at the Moxxi’s Big Encore respawn machine near his arena.

Step 5: Repeat until the Rainbow Vomit drops

Keep defeating Leader Willem until the Rainbow Vomit shotgun drops. Since the weapon’s elemental attributes vary with each drop, farming allows you to get the ideal elemental combination for your build.

Other ways to obtain the Rainbow Vomit shotgun

Beyond farming Leader Willem, there are two additional methods:

  • Legendary vending machine offers: Occasionally, the Rainbow Vomit appears as a rare stock in legendary-tier vending machines, especially during special events like the Vend of the Line.
  • Wildcard mission rewards: After completing the main campaign, you can unlock Wildcard missions. The mission “A Lot To Process” has the shotgun as a reward, offering a guaranteed but less repeatable source.

What makes the Rainbow Vomit shotgun special

  • It fires multiple elemental projectiles in every shot, potentially applying Cryo, Fire, Shock, and Radiation effects simultaneously.
  • Critical hits cause the shotgun’s pellets to ricochet, damaging multiple enemies around the target.
  • Its effectiveness scales with builds that boost elemental damage and critical hit chance.
  • The shotgun is visually distinctive with rainbow-colored star-shaped projectiles, making it a fan favorite for both aesthetics and power.

Tips to maximize Rainbow Vomit’s effectiveness

  • Build your character to increase critical hit chance and elemental status effect bonuses.
  • Use it in scenarios with clusters of enemies to maximize ricochet splash damage.
  • Be prepared to farm for multiple drops to get ideal elemental rolls for your playstyle.

Wrap-up: Your best approach to farming the Rainbow Vomit shotgun

If aiming for one of Borderlands 4’s flashiest and most diverse elemental shotguns, farming Leader Willem is your most reliable option, though it requires completing a substantial side mission chain first. Keep respawning and defeating him using Moxxi’s Big Encore. Alternate your farming strategy by checking legendary vending machines or finishing Wildcard missions once available. Prioritize builds around elemental and critical hit boosts to fully unleash this weapon’s potential in combat.