Proximity-triggered bomb packs the Reavers strapped to a mass of automatons — and which Carl detonated first.
During the barracks-hill fight, Carl's trap sense tingles and multiple lights glare through the smoke from the far right corner of the battlefield. His advanced Find Trap skill fires info boxes one after another: someone is arming a great many Automatons, each equipped with satchel explosives on a proximity trigger trip — an attempt to blow a funnel into the defenders' base.
Carl checks his map, sees only purple enemy dots and a few reanimated mages in that half of the field, warns everyone to brace over Warlord Chat, and casts Tripper. The satchels all go off at once, far harder than he expected: everyone without a Steady buff is knocked flat, Carl's eardrums blow out, and the automatons' gathering point becomes a crater with every cyborg in it simply gone. A sizzling metallic torso lands on the roof behind him.
Bulky charge packs strapped to automaton frames, wired to proximity triggers, marked in Carl's vision by glaring trap-detection lights.
The enemy's mass demolition charge, turned into the defenders' decisive weapon.