Haruspex

The Haruspex is a creature of pure, insatiable hunger, a broad-backed monster whose entire biology is devoted to the consumption of living matter. A grasping, prehensile tongue lined with hooks lashes out to seize prey and haul them into a cavernous mouth ringed with grinding teeth, where flesh, bone, and armour alike are rendered down and absorbed.

Unlike beasts bred for ranged destruction, the Haruspex thrives in the press of close slaughter, and the more it feeds the more vigorous and dangerous it becomes, wounds sealing over as devoured biomass fuels its ruined body. For the Tyranids it serves a grim dual purpose: a shock-beast that shatters enemy lines, and a mobile reclamation organism that begins the harvest of a world's biomass even as the battle still rages. To face a Haruspex is to watch a living stomach lurch toward you, growing only harder to kill with every soldier it swallows.