Traits

Your character's horns become a transparent glasslike material, with any possible liquid filling the inside. (Within reason). Objects could be inside the water if desired.

The liquid inside can be replaced with another elemental effect, but the character must also have, for example, Fire Mastery for the inside to contain fire.

Your character grows manta wings, or their wings change to resemble a shape like that of a manta ray.

Your character's hair flows like water. It can be perpetually flowing, or be the texture and look of water.

Wherever your character treads, ice follows. Their touch can be enough to freeze over water, or they can simply be chilly to the touch. This can be turned on and off at will.