Waterform

You transform a willing creature you touch, along with everything it's wearing and carrying, into a flowing pool of water for the duration. The spell ends if the creature drops to 0 hit points. An incorporeal creature isn't affected.

While in this form, the creature's walking speed becomes 10 ft. and its swimming speed becomes 50 ft. The target can enter and occupy the space of another creature. The target has resistance to nonmagical damage, it is immune to fire damage, and it has advantage on Dexterity and Constitution saving throws. The target can pass through small holes, narrow openings, and even mere cracks, treating such obstacles as difficult terrain. While on solid ground and above water, the target cannot leave the ground and any movement it has not used at the end of each of its turns is immediately used to move it downhill (or in a random direction, if on level ground).

While in the form of flowing water, the target can't talk or manipulate objects, and any objects it was carrying or holding can't be dropped, used, or otherwise interacted with. The target can't attack or cast spells.