This creature is a powerfully built, roughly humanoid-shaped monolith of black stone. Its hands end in wicked, serrated and jagged claws. No facial features can be discerned.
Speed 20 ft.
Str 26, Dex 8, Con 19, Int 6, Wis 11, Cha 11
When reduced to 0 or less hit points, an obsidian quasi-elemental explodes in a cloud of razor-sharp bits of obsidian. All creatures within a 30-ft radius take 6d6 damage. A DC 18 Reflex save reduces it to half. The save DC is Constitution-based.
A successful hit against an obsidian quasi-elemental with a piercing or slashing weapon (or piercing or slashing natural attack) that deals damage equal to its current HD opens a wound that spurts molten glass. The wound bleeds for 1d4 rounds and any creature within 5 feet must make a DC 18 Reflex save or take 2d8 fire damage from the splash. A new save must be made each round the wound bleeds and a creature is within the area. The save DC is Constitution-based.