Bound Colossus

Gargantuan elemental, lawful evil

Armor Class

17 (natural armor)

Hit Points

396 (18d20 + 180)

Speed

0 ft.

Saves

Str +14, Con +16

Skills

Athletics +14

Damage Resistances

acid, bludgeoning, piercing and slashing damage from nonmagical weapons

Damage Vulnerabilities

thunder

Damage Immunities

poison

Condition Immunities

charmed, exhaustion, frightened, paralyzed, poisoned, prone, restrained, unconscious

Senses

tremorsense 240 ft., darkvision 120 ft.

Languages

Terran

Challenge

21

Magic Resistance

The magnetic field surrounding the colossus slightly bends the weave of magic around it, granting it advantage on saving throws against spells and other magical effects.

Earth Glide

The colossus can burrow through nonmagical, unworked earth and stone. While doing so, the colossus doesn't disturb the material it moves through.

Siege Monster

The colossus deals double damage to objects and structures.

Elasticity

By morphing, the arms of the colossus can reach out to incredible distances. For every sixty feet, that is between the base of the colossus and its target, its attacks lose 1 die of damage to a minimum of 2.

Magnetism

The colossus emits its own magnetic field to a radius of 240 feet. If a creature that is wearing or carrying metal equipment enters this space or begins its turn there, they must make a DC 14 Strength saving throw. On a failure, they are drawn 30 feet closer to the base of the colossus. A creature who fails this saving throw may choose to drop the worn or carried items to automatically succeed on this check instead. If a creature hits the base of the colossus after failing this saving throw, they are restrained and must succeed a DC 14 Strength saving throw in order to escape.

Multiple Arms

The bound colossus has four arms. Each arm can be attacked (AC 17; 30 hit points; vulnerability to thunder damage). Destroying an arm deals 15 damage to the colossus. The colossus can construct a new arm by using an action to pull one out of its body but it must have a free arm to do so.

Actions

Multiattack

The Bound Colossus makes as many slam or earthen grasp attacks as it has remaining arms.

Slam

Melee or Ranged Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 26 (5d6+8) bludgeoning damage.

Earthen Grasp

The colossus reaches through the ground and reaches for one creature within 5 feet of its hand. The target must succeed on a contested grapple check. On a failed check, the target takes 26 (5d6+8) bludgeoning damage and is restrained. On subsequent turns, the colossus can attempt to crush a restrained target, which must make a DC 22 Strength saving throw. The target takes 26 (5d6+8) on a failed save, or half as much damage on a successful one. A restrained target can use their action to attempt to escape by making another contested grapple check and succeeding.

Legendary actions

Legendary Actions (3)

The Bound Colossus 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. The Bound Colossus regains spent legendary actions at the start of its turn.

Attack

The colossus makes one slam attack.

Magnetic Pulse (Costs 2 Actions)

The colossus emits a sudden magnetic pulse (see Magnetism).

Grow Arm (Costs 3 Actions)

The colossus regrows one of the arms it has lost; it doesn't need a free arm in order to do so.