STASH
Durationup to 3 min
TriggerScheduled
Effects
A second, small HP bar (0.5% of max HP). Hits damage it and the boss.
Rewards
Break it: every hitter gets an IRON CHEST, the top hitter also a CURSED CASKET.
How often
8.9% when a scheduled event is selected.
Source: official game library. Scheduled percentages describe event selection, not the chance per attack.