Umber Hulk

An enemy (combat level 82), found in Fire Forge, The Cinder Deeps. It has 2,600 health, 82 armor and 26 magic resist, and hits for 66.

Each kill gives 13,260 Mastery XP to the mastery of the weapon you are holding. Everyone who damages it gets the full XP and their own loot roll; party members standing nearby get the XP too. On a Slayer task it also pays Slayer XP — see below.