Chaos Elemental

Earth Carve. The elemental can burrow through nonmagical, unworked earth and stone. While doing so, the elemental slightly melts the material it moves through. The elemental can melt nonmagical, unworked earth and stone in its space if it remains there for 2 hours.

Form of Fluid. The elemental can move through a space as narrow as 1 foot wide without squeezing. A creature that touches the elemental or hits it with a melee attack while within 5 feet of it takes 5 (1d10) fire damage. In addition, the elemental can enter a hostile creature's space and stop there. The first time it enters a creature's space on a turn, that creature takes 5 (1d10) fire damage.

Freeze. If the elemental takes cold damage, it partially freezes; its speed is reduced by 20 feet, and all fire damage dealt by the elemental is instead cold damage until the end of its next turn.

Illumination. The elemental sheds bright light in a 25-foot radius and dim light in an additional 25 feet.

Minor Water Susceptibility. For every 5 feet the elemental moves in water, or for every gallon of water splashed on it, it cannot deal fire damage using its features until the end of its next turn.

Multiattack. The elemental makes two slam attacks.

Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) bludgeoning damage plus 10 (2d6 + 3) fire damage. 

Whirling Whelm-Wind (Recharge 4–6). Each creature in the elemental's space must make a DC 15 Strength saving throw. On a failure, a target takes 12 (2d8 + 3) bludgeoning damage plus 10 (2d6 + 3) fire damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the elemental's space.

The elemental can grapple one Huge or Large creature or up to six Medium or smaller creatures at one time. At the start of each of the elemental's turns, each target grappled by it takes 12 (2d8 + 3) bludgeoning damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength and succeeding.

The elemental can use this action on a subsequent turn to fling all creatures restrained by this ability up to 20 feet away from the elemental in a random direction and knock them prone. If a thrown target strikes an object, such as a wall or floor, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 13 Dexterity saving throw or take the same damage and be knocked prone.

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Legendary Action Name (Costs # Actions). Enter the description for your legendary action.