Spawn of Thangorodrim
The Ruins of Belegost#28 (x2/x0)

When Revealed: If Naurlhûg is in play, it makes an immediate attack against the first player. If Naurlhûg is not in play, place 1 resource on Stalking the Ruins. Then, if there are at least 3 resources on Stalking the Ruins add Naurlhûg to the staging area.

Shadow: Attacking enemy makes an additional attack against you after this one.