Buoyancy

You cause a creature or an object you can see within range to sink or float for the duration. Choose either a creature or an object that is neither worn nor carried. If the target is unwilling, it can make a Constitution saving throw. On a success, the spell has no effect. If the target is a creature, everything it is wearing and carrying changes buoyancy with it. Any item dropped by an affected creature returns to normal buoyancy at once.

Sink. The target becomes very dense. If the target is submerged in water, it sinks downward at a rate of 10 feet per round for the duration. This movement does not count against the creature’s movement speed for the round. If the target is size category Large or above, this descent increases in speed by 10 feet per round for each size category above Medium.

Float. The target becomes very buoyant. If the target is submerged in water, it floats upwards at a rate of 10 feet per round for the duration. This movement does not count against the creature’s movement speed for the round. If the target is size category Small or below, this ascent increases in speed by 10 feet per round for each size category below Medium.