Grond

"It was a huge ram, founded of black steel, shaped in the likeness of a ravening wolf creature, long forging in the dark smithies of Mordor. Grond, they named the ram, in memory of the Hammer of the Underworld, wielded by Morgoth. The ram was great as a forest tree, a hundred feet in length, swinging on mighty chains from within the frame. Spells of ruin were engraved all over it. And from the ram's eyes and its gapping jaws… fire flickered, lit by the same dark sorcery that lit the fires within the trenches at Pelennor Fields." Rurouni Kenshin and Lord of the Rings

Grond:
1. The Hammer of the Underworld. The weapon of Morgoth
2. The ram forged by Sauron and named after the Hammer of the Underworld. It was used to destroy the gates of Minas Tirith. Grond was made in the form of a ravening wolfs head.