Rock is the strongest troll on Death Plateau. As he is the strongest troll in the area, caution is advised when fighting him, as he can hit a max of 252 and has a fair amount of life points. Since he only attacks with melee, Protect from Melee or Deflect Melee may help. Like the rest of the "big, bad" trolls in the area, such as Stick, Pee Hat, and Kraka, he may drop a rune warhammer or granite shield. The ordinary mountain trolls do not drop those two items, despite beliefs to the contrary.
Since trolls are named after the first thing they eat, he probably ate a rock.