A BCI-coordinated flash mob that erupts when a synthetic being is publicly harassed, detained, or destroyed — participants flood the location within minutes, forming a silent human-and-synthetic wall around the victim or the site of violence. The signal, called a Marrow Ping, travels through encrypted mesh-BCI relays and cannot be traced to a single origin node. Originating from the Shelf district of Rust Corridor after the 2208 Praxis Incident — where a Tier 2 synthetic named Vela-9 was publicly dismantled by corporate security for 'unauthorized sentience displays' — the mob has since spread to Tier 3 neighborhoods. Participants say nothing, carry nothing, and disperse exactly twelve minutes after arrival.