Begin Again/World Building/Disruptors
The Disruptor is a tool engineered by Octarians for use against Inkling victims. It is a subsonic-frequency emitter that vibrates the entirety of one's person. When affected, the victim cannot change from their current form, as their cells cannot settle long enough to initiate the change.
This also means that a Spirit simply cannot form if the victim is splatted, causing an instant death.