Divine spell that silences and stills the battlefield; Eris switches it off, so everyone wakes when the ball breaks.
The Witness spell's effects still blanket the field. It interrupted the lava abatement work protecting Larracos, leaving a slow-moving glob of molten rock about to enter Shanty Town and head for the giant hole in the ground. It also mutes the battlefield — Carl can see Nami screaming but hears nothing until a Flesher is on her, and Bianca's howl never reaches him.
Critically, Eris has turned the spell off. That means everyone inside the Rolling Battle Formation Ball will be awake the instant it breaks open, guaranteeing chaos with two gods in the middle of it — one of the main reasons Carl decides scattering, not fighting, will be necessary. Epitome Tagg was outside when the spell was cast, which is how Carl deduces he is in the ball.
The spell shaping the whole battlefield's silence and stillness, now switched off with consequences pending.