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 feet until the end of its next turn.

Surge of Youth (1/day). When the young Water Elemental's hit points drop below half (26 HP), it gains a burst of energy, momentarily becoming more ferocious in battle. For 1 minute, the Water Elemental gains advantage on attack rolls, and its movement speed increases by 10 feet (to 40 ft., swim 50 ft.). After this surge ends, the Water Elemental becomes sluggish, and its movement speed is reduced by 10 feet until the end of the encounter (to 20 ft., swim 30 ft.).

Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 3) bludgeoning damage.

Whelm (Recharge 4–6). Each creature in the elemental's space must make a DC 12 Strength saving throw. On a failure, a target takes 10 (2d6 + 3) bludgeoning damage. If it is Large or smaller, it is also grappled (escape DC 12). 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 5 feet out of the elemental's space.

The elemental can grapple one medium or smaller creature at one time. At the start of each of the elemental's turns, each target grappled by it takes 4 (1d6 + 1) 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 12 Strength check and succeeding. f the elemental moves, the grappled creature moves with it. The elemental can release the grapple as a free action.

Water Whirl (1/day). The young Water Elemental creates a swirling water vortex in a 10-foot radius and a 10-foot tall cylinder centred on itself. Each creature in the vortex must make a DC 12 Strength saving throw. On a failed save, a creature takes 7 (2d6) (2d6) bludgeoning damage and is pulled 10 feet toward the centre. On a successful save, the creature takes half damage and isn’t pulled. The vortex lasts until the start of the elemental's next turn.

Water Surge (1/day). The Young Water Elemental uses a bonus action to surge forward in a burst of speed, moving up to its speed in a straight line. This movement does not provoke opportunity attacks.

Watery Defense. When an attack hits the Young Water Elemental, it can use its reaction to momentarily become amorphous, reducing the damage from the attack by 1d6. After using this reaction, the elemental's form briefly becomes unstable, causing it to have disadvantage on its next attack roll.