The lethal curse that strikes Dong when his sapient sock abandons him — untreatable by any temple, and likely fatal.
'Negative ROI' is the debuff that appears over Dong Quixote's head as his health begins to drain after his sapient Sock tears open, sheds its hoarded nickels to a hundred scattering NPCs, and finally attacks Bucket Boy before teleporting away for good under the safe-room rules. Mordecai and the advisor Mistress Tiatha identify it as a curse truly called 'Separation Anxiety': the sapient weapon has used Dong up and moved on, and the bond's severance is killing him. Crucially, unlike an ordinary curse, no temple can cure it — the only remedy is to recover the sock *and* every single coin it lost, which is functionally impossible now that the nickels are scattered and the sock has likely teleported to Hungry Eyes and into a new owner's hands.
It threatens both Dong's life and the quest that depends on keeping him alive, and Carl — who gave Dong the cursed sock in the first place (having gotten it from Quan Ch) — bears the guilt.
A debuff banner reading 'Negative ROI' hovering over Dong as his health steadily dips.
The untreatable separation curse killing Dong after his sapient sock abandons him.