Illusion-generated armored vehicles that soak the enemy's high-tech grenade barrage while advancing nothing.
As new orange-tinged explosions ripple around Carl — detonations he cannot hear but feels in his chest — he identifies them as grenades of some high-tech variety he has never seen before. The enemy is throwing them at the tanks. The tanks which don't really exist.
The phantom armor is part of the crawlers' layered War Protections, and it works exactly as designed: the enemy expends its most advanced ordnance on illusions instead of on the infantry actually crossing No Man's Land. The deception collapses when the Deshrouded diffusion spell strips every illusion from the field at once.
Convincing illusions of armored fighting vehicles advancing with the assault.
Decoys that absorb enemy heavy ordnance during the charge.