Scatha

Flying
Whenever a dragon you control becomes the target of a spell or ability an opponent controls, Scatha deals 3 damage to that player.
Frumgar, they say, was the name of the chieftain who led his people to Eotheod. Of his son, Fram, they tell that he slew Scatha, the great dragon of Ered Mithrin, and the land had peace from the long-worms afterwards.