Talon

Before Russ could react, Horus punched forward with his family, slamming it hard into the injured side of Leman Russ. The boom of the claws' energy rolled out over the battlefield, drowning out the noise of the battle. Russ roared with pain as the talon raked fresh cuts through his armour gouged deeply into his flesh. The barbs ripped away chunks of muscle, the energy fields scorched his bones. With a contemptuous flick, Horus threw him off the ends of his claws, hurling Russ across the chamber.
Russ skidded to a halt at the foot of a profane painting, the Emperor's Spear clattering down beside him. Smoke issued from the rents carved into the armour of Elavagar by Horus' talon.

Wolfsbane