The Croaking Trident
A two-handed trident surrounded by pandemonic energy, it deals d10 regular + d4 pandemonic damage. Hidden beneath the luminescent ferns along the east wall of the Sepulchre of the Swamp Witch's Hidden Ferns chamber.
Each living creature it slays gradually turns the wielder into a mad amphibian humanoid. The changes start subtly, but after 5 kills, people begin noticing the bulging eyes, the slimy sweat, and discoloration of the skin. After 8 kills, the wielder has a natural −d2 armor due to their rubbery skin, and croaks between their words as they sometimes incoherently speak. At 13 kills, the transformation is complete, and nothing remains of the person but chaotic amphibian rage, madness, and violence.
Srolki & Yaoxl and Srolki & Yaoxl (the toad-guardians below the Downward Spiral) are willing to do almost anything to get their hands on the Croaking Trident.
Whether the trident's final transformation produces a Srolki/Yaoxl-style toad or something simpler/worse is implied but unscripted. The trident's origin (Swamp Witch's? toad-cities'? older?) is open.