Breathless Kiss

Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: the target is grappled (escape DC 13) and the rusalka draws all the air from the target's lungs with a kiss. If the rusalka has movement remaining, she drags the grappled creature into deep water, where it begins suffocating.

Drowning Hair (1/Day)

The rusalka's long hair tangles around a creature the rusalka has grappled. The creature takes 33 (6d10) necrotic damage, or half damage with a successful DC 15 Constitution saving throw. In addition, until it escapes the rusalka's grapple, it is restrained and has disadvantage on Strength checks to break free of the grapple.