Actions

Multiattack. Juiblex makes three Acid Lash attacks.   Acid Lash. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 23 (4d6 + 9) acid damage. Any creature killed by this attack is drawn into Juiblex's body, where the corpse is dissolved after 1 minute.   Eject Slime (Recharge 5–6). Juiblex spews out a corrosive slime, targeting one creature that it can see within 60 feet of it. The target must succeed on a DC 24 Dexterity saving throw or take 55 (10d10) acid damage. Unless the target avoids taking all of this damage, any metal armor worn by the target takes a permanent −1 penalty to the AC it offers, and any metal weapon the target is carrying or wearing takes a permanent −1 penalty to damage rolls. The penalty worsens each time a target is subjected to this effect. If the penalty on an object drops to −5, the object is destroyed. The penalty on an object can be removed by the mending spell.

Legendary Actions

Juiblex can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Juiblex regains spent legendary actions at the start of its turn.   Acid Splash. Juiblex casts acid splash.   Attack. Juiblex makes one Acid Lash attack.   Corrupting Touch (Costs 2 Actions). Melee Weapon Attack: +17 to hit, reach 10 ft., one creature. Hit: 21 (4d6 + 7) poison damage, and the target is slimed. Until the slime is scraped off with an action, the target is poisoned, and any creature, other than an Ooze, is poisoned while within 10 feet of the target.  

MYTHIC ACTIONS

If Juiblex's Demonic Awakening trait has activated in the last hour, he can use the options below as legendary actions.   Spell (Costs 2 Actions). Juiblex casts a spell.   Madness (Costs 2 Actions). Each creature, other than an Ooze within 120 feet of Juiblex and aware of him must succeed on a DC: 21 Wisdom saving throw or descend into a madness determined by the Madness of Juiblex table for 1 minute. A effected creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. These later saves have disadvantage if Juiblex is within line of sight of the creature.   Regain. Juiblex automatically recharges his use of Eject Slime.

Lair Actions

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

• 10 green slimes (see the Dungeon Master's Guide) appears on a spot on the ceiling that Juiblex chooses within the lair. The slime disintegrates after 1 hour.
• Juiblex slimes a square area of ground it can see within the lair. The area can be up to 20 feet on a side. When the slime appears, each creature on it must succeed on a DC 24 Dexterity saving throw or fall prone and slide 20 feet in a random direction determined by a d8 roll. When a creature enters the area for the first time on a turn or ends its turn there, that creature must make the same save. The slime lasts for 1 hour or until it is burned away with fire. If the slime is set on fire, it burns away after 1 round. Any creature that starts its turn in the burning slime takes 22 (4d10) fire damage.
• Juiblex slimes a square area of ground it can see within the lair. The area can be up to 20 feet on a side. When the slime appears, each creature in that area must succeed on a DC 24 Strength saving throw or become restrained. When a creature enters the area for the first time on a turn or ends its turn there, that creature must make the same save. A restrained creature is stuck as long as it remains in the slimy area or until it breaks free. The restrained creature, or another creature that can reach it, can use its action to try to break free and must succeed on a DC 24 Strength check. The slime lasts for 1 hour or until it is burned away with fire. If the slime is set on fire, it burns away after 1 round. Any creature that starts its turn in the burning slime takes 22 (4d10) fire damage.

Juiblex's principal lair is known as The Slime Pits of Juiblex within Shedaklah which belongs to Zuggtmoy. The Slime Pits are a bubbling morass of fetid sludge. The landscape is covered in vast expanses of caustic slimes, and strange organic forms rise from the oceans of ooze at Juiblex's command.

Regional Effects

The region containing Juiblex's lair is warped by its magic, creating one or more of the following effects:

• Small bodies of water, such as ponds or wells, within 1 mile of the lair turn highly acidic, corroding any object that touches them.
• Within 6 miles of the lair, all Wisdom (Medicine) and Wisdom (Survival) checks have disadvantage.
• Surfaces within 6 miles of the lair are frequently covered by a thin film of slime, which is slick and sticks to anything that touches it.