You choose a point on the ground or on the surface of water that you can see within range, and transform a 20-foot radius area on the surface around the point into a portal into the deep ocean. When a creature moves through the portal, it appears in the depths: a 20-foot-radius column of water that extends downward indefinitely, with an opening at the top in the shape of the portal. A creature can enter or exit the depths by passing through the portal.

If the portal is on the surface of a body of water, the water within the depths count as part of that body of water.

When a creature starts its turn within the depths, it must make a Constitution saving throw. On a failed save, a creature take 4d6 cold damage, sinks 50 feet into the water, and becomes stunned until the start of its next turn. Additionally, if a creature starts its turn at a depth of 100 feet or more, it takes 1d6 bludgeoning damage for every 10 feet of depth past 100 feet, to a maximum of 20d6. Creatures that are native to the deep sea automatically succeed on this saving throw and are immune to all damage from this spell.

As a bonus action on each of your turns before the spell ends, you can cause water from the portal to leap out and grab at a creature you can see within 10 feet of it. The creature must succeed on a Strength saving throw or be dragged through the portal, into the depths.

When the spell ends, any creatures and objects within the depths are shunted to the nearest unoccupied spaces within 5 feet of the portal.

If you touch a body of water when casting this spell, you can choose a point within 60 feet of you that is in the same body of water. The spell is cast as if you were at the chosen point, but you must use your own senses.