Magma Paraelemental (5e Creature)
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Large elemental, neutral
Damage Vulnerabilities thunder
Molten Form. The elemental can freely pass through unworked, nonmagical lava, superheated rock, or other molten materials and even walk upon its liquid surface. While doing so, it is unaffected by difficult terrain or movement-impairing effects that would be caused by volcanic conditions. A creature who touches the elemental or hits it with a melee attack suffers 3 (1d6) fire damage. In addition, any nonmagical weapon made of metal, stone, or wood that hits the paraelemental begins to melt. After dealing damage, the weapon takes a cumulative -1 penalty to damage rolls. If its penalty reaches -5, the weapon is destroyed. Nonmagical ammunition made of metal, stone, or wood that hits the elemental is destroyed after dealing damage.
Water and Cold Susceptibility. For every 5 feet the elemental moves in water, or for every gallon of water splashed on it, the elemental takes 1 cold damage. In addition, whenever the elemental takes cold damage, it partially freezes and its speed is reduced by 20 feet until the end of its next turn.
Multiattack. The elemental makes two slam attacks.
Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) damage, plus 4 (1d8) fire damage. Nonmagical armor worn by the target is partially melted and takes a permanent and cumulative -1 to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.
Heat Wave (Recharge 4-6). The elemental can release a burst of extreme heat in a 15-foot radius centered upon itself. Creatures within range wielding a metal weapon or wearing a suit of heavy or medium metal armor feel it grow red-hot and take 9 (2d8) fire damage if in physical contact with the object. Should a creature take damage in this way, it must succeed on a DC 15 Constitution saving throw or drop the object if it can. If it doesn't drop the object, it has disadvantage on attack rolls and ability checks until the start of its next turn.
When primordial flame and stone collide on the fringes of the Elemental Planes of Earth and Fire, a magma paraelemental takes form. Their hearts are furnaces of volcanic force that churn deep inside bulbous, lumpy shells of molten rock. As they plod onward, they leave nothing but melted devastation in their wake.