A floor-wide field that goes up at the start of Ramp-Up to disallow offensive and transport magic.
Baroness Victory explains that the ban on magic during Ramp-up Phase is not a rule enforced by referees but a physical condition: a suppression field will cover the entire floor and simply disallow the affected magic. Crawlers can still cast freely right now during The Ceasefire, but the ability vanishes the moment phase two begins.
The field targets two categories: magic designed to cause direct harm to another, and magic or skills designed to transport you from one space to another. Enchanted weapons still function, but separate spells attached to them do not. Skills survive where spells do not, which is why Gloom Wraith Phase still works as a phase while Puddle Jumper and the Gate of the Feral Gods go dead.
The mechanism that strips the crawlers of their magical edge for 180 hours.