This seething mass of bubbling molten rock churns and moves of its own hungry accord.
Magma Ooze CR 7
AC 4, touch 4, flat-footed 4 (–5 Dex, –1 size)
hp 85 (9d8+45)
Fort +8, Ref –2, Will –2
Defensive Abilities split (cold and slashing, 8 hp); Immune fire, ooze traits
Weaknesses vulnerability to cold, vulnerability to water
The magma ooze is formed of molten rock. Whenever a creature strikes a magma ooze with a weapon, that weapon takes 4d6 points of fire damage unless the attacker makes a DC 19 Fortitude save. Damage caused to weapons in this manner is not halved, but hardness does help prevent some of the damage dealt. The save DC is Constitution-based.
A significant amount of water, such as that created by a create water spell, the contents of a large bucket, or a blow from a water elemental, that strikes a magma ooze forces the creature to make a DC 20 Fortitude save to avoid being staggered for 2d4 rounds. A magma ooze that is immersed in water must make a DC 20 Fortitude save each round (this DC increases by +1 each subsequent round) or become petrified, reverting once the water is gone.
Environment any volcano or underground
Magma oozes are living pools of molten rock. They roam the borders of the Plane of Earth and Plane of Fire, and on the Material Plane they sometimes arise spontaneously from strange magic, usually in the vicinity of volcanoes. Magma oozes avoid water, and if forced into enough of it, they become encased in a cooled stony shell, unharmed but immobilized, waiting indefinitely until the water retreats.
A typical magma ooze grows to 10 feet across and is about 6 inches thick.