Elder Acid Elemental
Huge elemental, neutral
Armor Class
17
Hit Points
162 (13d12 + 78)
Speed
20 ft., swim 80 ft.
STR
22 (+6)
DEX
15 (+2)
CON
22 (+6)
INT
6 (-2)
WIS
11 (+0)
CHA
11 (+0)
Damage Immunities
acid, poison
Damage Resistances
bludgeoning, piercing, and slashing from nonmagical weapons
Condition Immunities
exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained, unconscious
Senses
darkvision 60 ft., passive perception 10
Skills
Stealth +6
Languages
--
Challenge
13 (10,000 XP)
Acid. A creature that touches the acid elemental or hits it with a melee attack while within 5 feet of it takes 5 (2d4) acid damage. Any nonmagical weapon made of metal or wood that hits the acid elemental corrodes. After dealing damage, the weapon takes a permanent and cumulative –1 penalty to damage rolls. If its penalty drops to –5, the weapon is destroyed. Nonmagical ammunition made of metal or wood that hits the acid elemental is destroyed after dealing damage. The acid elemental can eat through 2-inch-thick, nonmagical wood or metal in 1 round.
Fumes. Creatures who begin their turn within 5 feet of the acid elemental must succeed on a DC 18 Constitution saving throw or be poisoned until the start of their next turn. On a successful saving throw, the creature is immune to the elemental’s fumes for 24 hours.
Vulnerability to Water. For every 5 feet that the elemental moves in water, or for every gallon of water splashed on it, it takes 1 fire damage.
Actions
Slam. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 24 (4d8 + 6) bludgeoning damage plus 49 (14d6) acid damage. In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative –1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.