Item Details
Weapon Rainbow Vomit (Jakobs Legendary Shotgun)
Dedicated drop Leader Willem
Boss arena The Excrucible — Grindstone of the Worthy, Carcadia Burn
Unlock chain Enter the Electi Pt. 1 → Enter the Electi Pt. 2 → The Council Divided → A Traitor Within → The Mole’s Gambit
Farm method Use Moxxi’s Big Encore machine near Willem’s arena to respawn and repeat
Alternate source Wildcard Missions (post‑campaign), claim from Rewards inventory after completion; may also appear as a weekly highlighted legendary
Legendary effect Color Spray — fires three elemental droplets at once; the elements are randomized per drop (examples: Corrosive, Cryo, Radiation)
Other Can drop as a world drop, but it’s much rarer than the dedicated farm

Drop location for Rainbow Vomit (Leader Willem)

Rainbow Vomit has a dedicated source: Leader Willem in The Excrucible, a boss arena inside the Grindstone of the Worthy region of Carcadia Burn. If you only care about consistent drops, this is the farm to set up.

Side missions required to unlock Leader Willem

You won’t meet Willem until late in a Carcadia side story. Complete these missions in order to access his arena during “The Mole’s Gambit” and unlock it for repeats:

  • Enter the Electi Pt. 1
  • Enter the Electi Pt. 2
  • The Council Divided
  • A Traitor Within
  • The Mole’s Gambit

Finishing The Mole’s Gambit opens Willem’s fight for farming.

Farm Leader Willem with Moxxi’s Big Encore

After your first clear, return to The Excrucible. Near the arena you’ll find Moxxi’s Big Encore machine; paying it respawns Leader Willem so you can run the encounter again. Repeat until Rainbow Vomit drops with the elemental roll you want.

Get Rainbow Vomit from Wildcard Missions (post‑campaign)

There’s a second, repeatable path once you’ve finished the main story. Completing the introductory Wildcard Mission unlocks Wildcard runs from anywhere in the game. Open your map and use the Wildcard icon in the bottom‑left UI to load directly into the mission at your current Ultimate Vault Hunter level.

For the standard loop: defeat the Oppressor, push on to Zadra’s hideout, and finish the mission. Rewards aren’t auto‑added; open your inventory’s Rewards section and claim Rainbow Vomit from the chest marked with the Wildcard symbol if it’s on the table. Rainbow Vomit can also rotate in as the highlighted legendary of the week.

What Rainbow Vomit’s Color Spray actually does

Rainbow Vomit’s intrinsic affix is Color Spray. Each shot launches three elemental droplets at once. The specific elements are set by the item’s roll and can vary; common combinations include Corrosive, Cryo, and Radiation. Because the elements are baked into the drop, dedicated farming is the practical way to chase a preferred setup.

Yes, it can world drop — but don’t rely on it

Like most legendaries, Rainbow Vomit is in the world drop pool, so it can appear from random enemies or chests. That chance is significantly lower than the dedicated farm from Leader Willem or the curated Wildcard rewards, so treat it as a bonus find rather than a plan.

The fast path is clear: unlock Willem through the Carcadia side chain, then loop his arena with Moxxi’s machine. If you’ve finished the campaign, fold in Wildcard runs and remember to claim from the Rewards tab to avoid missing a drop.