Fragment spray from cracking poison rocks, pinging off Carl's shields and triggering a memory of Texas fireflies.
When a group of Poison-Infused Rocks crashes around Carl's squad, cracking and breaking and trailing green fumes, shrapnel showers over them. It pings against his shields like fireflies — a comparison that sends his mind abruptly to his grandparents' house in Texas, which had fireflies where Washington did not.
Carl catches himself mid-charge: why would he think of that now? It is the chapter's one moment of stillness, a flicker of a life before The Crawl surfacing while Casualty Notification plinks stab through his chest and he runs on toward the Enemy Trench.
Battlefield hazard that triggers Carl's brief memory of home mid-assault.