Alpha Elemental

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

Air Form. The elemental can enter a Hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.

Water Form. The elemental can enter a Hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.

Freeze. If the elemental takes cold damage, it partially freezes; its speed is reduced by 20 ft. until the end of its next turn.

Fire Form. The elemental can move through a space as narrow as 1 inch wide without squeezing. A creature that touches the elemental or hits it with a melee Attack while within 5 ft. 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 and catches fire; until someone takes an action to douse the fire, the creature takes 5 (1d10) fire damage at the start of each of its turns.

Illumination. The elemental sheds bright light in a 30-foot radius and dim light in an additional 30 ft..

Water Susceptibility. For every 5 ft. the elemental moves in water, or for every gallon of water splashed on it, it takes 1 cold damage.

Siege Monster. The elemental deals double damage to objects and structures.

Multiattack. The elemental makes two slam attacks, or one slam attack and one touch attack, or two touch attacks.

Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.

Touch: Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) fire damage. If the target is a creature or a flammable object, it ignites. Until a creature takes an action to douse the fire, the target takes 5 (1d10) fire damage at the start of each of its turns.

Whirlwind (Recharge 4-6). Each creature in the elemental's space must make a DC 13 Strength saving throw. On a failure, a target takes 15 (3d8 + 2) bludgeoning damage and is flung up 20 feet away from the elemental in a random direction and knocked 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.
If the saving throw is successful, the target takes half the bludgeoning damage and isn't flung away or knocked prone.

Whelm (Recharge 4-6). Each creature in the elemental's space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning 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 Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental's turns, each target Grappled by it takes 13 (2d8 + 4) 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.

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. Spent legendary Actions are regained at the start of each turn.

Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.

Touch. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) fire damage. If the target is a creature or a flammable object, it ignites. Until a creature takes an action to douse the fire, the target takes 5 (1d10) fire damage at the start of each of its turns.

Whirlwind (Cost 2 actions, only if recharge is available). Each creature in the elemental's space must make a DC 13 Strength saving throw. On a failure, a target takes 15 (3d8 + 2) bludgeoning damage and is flung up 20 feet away from the elemental in a random direction and knocked 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.
If the saving throw is successful, the target takes half the bludgeoning damage and isn't flung away or knocked prone.

Whelm (Cost 2 actions, only if recharge is available). Each creature in the elemental's space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning 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 Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental's turns, each target Grappled by it takes 13 (2d8 + 4) 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.

Conjure Elemental (cost 3 actions, only one conjured elemental can exist at a time). The elemental call forth an elemental servant. Choose an area of air, earth, fire, or water that fills a 10-foot cube within range. An elemental of challenge rating 5 or lower appropriate to the area it choses appears in an unoccupied space within 10 feet of it. For example, a fire elemental emerges from a bonfire, and an earth elemental rises up from the ground. The elemental disappears when it drops to 0 hit points or when the spell ends.