Deathleaper

Not every Tyranid bio-form exists to kill in bulk. Deathleaper was grown for a subtler purpose: to slip unseen into an enemy's rear lines, stalk its officers and psykers, and end them in silence long before the swarm's main tide arrives. Its lithe, chameleonic body allows it to melt into shadow and structure alike, and those who have glimpsed it rarely survive to describe more than an impression of claws and a presence that felt, disturbingly, as though it were amused.

Deathleaper's kills are rarely quick mercies. Survivors of encounters near its hunting grounds report bodies left deliberately displayed, command posts thrown into panic by officers found impossibly slain behind sealed defenses, and a creeping paranoia that spreads through a garrison faster than any physical wound could. This is, by all accounts, entirely intentional; a demoralized command structure collapses before the swarm even needs to fight it directly.

Most unsettling to those who study it is Deathleaper's apparent ability to survive being killed. Multiple engagements have reported the creature's apparent destruction, only for identical predations to resume on distant worlds sometime later, feeding grim speculation that this singular hunter, like the Swarmlord, is simply too effective a design for the Hive Mind to ever let go for good.