Zargon the Returner

Traits

Legendary Resistance (4/Day)

If Zargon fails a saving throw, it can choose to succeed instead.

Regeneration

Zargon regains 20 hit points at the start of each of its turns. If Zargon takes cold or fire damage, this trait doesn't function at the start of Zargon's next turn. Zargon dies only if it starts its turn with 0 hit points and doesn't regenerate.

Shrouded Being

Zargon can't be targeted by divination magic or perceived through magical scrying sensors.

Slimy Demise

When Zargon dies, its body dissolves into foul slime, leaving only its horn behind. Zargon re-forms in 1d10 days, regrowing from the horn. The horn is immune to all damage and can be destroyed only by submerging it in a cleansing waterfall on one of the Upper Planes for 101 days. While the horn is submerged in this way, Zargon doesn't re-form, and the horn slowly dissolves, sending corrupting slime downriver that permanently fouls the water for 10 miles from the place where the horn dissolved. The fouled water is unfit to drink, chokes aquatic wildlife, and withers plants.

Actions

Multiattack

Zargon makes two Barbed Tentacle attacks, one Bite attack, and one Gore attack.

Barbed Tentacle

Melee Weapon Attack: +12 to hit, reach 20 ft., one target. Hit: 15 (2d8 + 6) piercing damage. If the target is a Large or smaller creature, it has the grappled condition (escape DC 20), and Zargon can pull the creature up to 20 feet straight toward itself. Zargon has six tentacles, each of which can grapple one creature. Zargon can move at its full speed while dragging creatures it is grappling.

Bite

Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 19 (2d12 + 6) piercing damage plus 7 (2d6) acid damage.

Gore

Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 6) force damage, and a 10-foot-radius invisible sphere of antimagic, like that created by an Antimagic Field spell, surrounds the target. The sphere is centered on the target, moves with the target, and lasts until the end of Zargon's next turn.

Slime Wave (Recharge 5–6)

Zargon spews slime in a 60-foot cone. Each creature in that area that isn't an Aberration or Ooze must make a DC 19 Constitution saving throw. On a failed save, the creature takes 38 (7d10) acid damage and has the poisoned condition for 1 minute. On a successful save, the creature takes half as much damage only. A poisoned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

A creature reduced to 0 hit points by the acid damage dies and dissolves into a puddle of slime that rises as a gibbering mouther at the start of Zargon's next turn. The creature obeys Zargon's commands and takes its turn immediately after Zargon's. Only a Wish spell can reverse this transformation and restore the creature to life.

Reactions

Defiant Essence

When a creature casts a spell that targets Zargon or would deal damage to it, Zargon attempts to absorb the magic into its horn. The creature must make a DC 19 Charisma saving throw. On a failed save, the creature takes 6 (1d12) force damage, and the spell it cast fails and is wasted.

Slime Spray

When a creature ends its turn within 30 feet of Zargon, Zargon sprays toxic slime at the creature. The target must make a DC 19 Dexterity saving throw (with disadvantage if it has the poisoned condition). On a failed save, the creature takes 7 (2d6) poison damage. On a successful save, it takes half as much damage.

Lair actions

On initiative count 20 (losing initiative ties), Zargon can take one of the following lair actions; it can't take the same lair action two rounds in a row:

• Dissolution: Zargon dissolves into a glob of slime, seeps to an unoccupied space anywhere in the lair without provoking opportunity attacks, then re-forms.
• Spell Breaker: Zargon targets up to two creatures it can see within the lair. All spells of 5th level or lower affecting the targets end.
• Sucking Slime: Zargon creates a 20-foot-radius puddle of slime on the ground centered on a point within the lair. The slime is difficult terrain, and each creature in that area when the slime appears has the grappled condition (escape DC 15). Aberrations and Oozes are unaffected by the slime. The slime lasts until Zargon dies or until it uses this lair action again.

Regional effects

The region containing Zargon's lair is warped by Zargon's unnatural presence, creating one or more of the following effects:

• Arcane Enervation: Enemies of Zargon within 1 mile of the lair have disadvantage on saving throws made to maintain concentration.
• Corrupted Water: Rain and water sources within 1 mile of the lair are tainted. A creature that drinks the water must succeed on a DC 15 Constitution saving throw or have the poisoned condition until it finishes a long rest.
• Eerie Weather: The area within 10 miles of the lair experiences strange weather patterns that defy the region's typical climate.

If Zargon dies, these effects fade over the course of 1d10 days.