Fuel to the Forge: Any nonmagical weapon that hits the Wombworm begins to melt and deform. After successfully hitting the creature, the weapon takes a permanent and cumulative −1 penalty to damage rolls. In addition, every time the Wombwyrm induces a penalty to damage rolls or AC, it consumes the material and regains 1d4 hit points. If its penalty drops to −5, the weapon is destroyed. Nonmagical ammunition that hits the creature is instantly destroyed and consumed by the creature. Nonmagical unarmed strikes made against the Wombwyrm begin to melt the attacking creature, causing 1d4 fire damage and healing the Wombwyrm for 1d4 hit points. Immutable Form: The Wombwyrm is immune to any effect that would change its form. Illumination: The Wombwyrm sheds bright light in a 15 ft. radius around it and dim light for an additional 15 ft. Crucible's Womb (Turn 1:) The Wombworm spawns 2d4 Puer de Scoria within 5 ft. of it. Fuligine's Shroud (Turn 2:) An 30 ft. aura of smoke heavily obscures all creatures around the Wombwyrm, lasting until it's next turn. Burn Anew (Turn 3:) All living Per de Scoria on the field return to the Wombwyrm and are re-absorbed on the Wombwyrm's turn, healing the Wombwyrm for half of each creature's hit points.
Multiattack: The Wymbworm can make 2 attacks: One bite, and one tail. Bite: Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 4) piercing damage plus 3 (1d6) fire damage. Tail: Swallow: Cone of Fire: The Wymbworm exhales fire in a 15-foot cone. Each creature in that area must make a DC 13 Dexterity saving throw, taking 16 (4d6) fire damage on a failed save, or half as much damage on a successful one.