It looks as though Thor's Well, on the central Oregon coast, is draining it.
In both cases, the roof of the cave collapsed; the Spouting Horn was a smaller cave, and located a bit higher in elevation. Its roof collapse therefore produced a small hole, and as the surf enters the cave opening, seawater shoots through the hole in the roof, producing the spout.
The cave that formed Thor's Well was considerably larger and deeper, and when its roof collapsed, it left a huge hole, into which it appears as though the ocean is being drained.
It can be seen at Cape Perpetua Scenic Area, a rather large coastal state park located just south of the town of Yachats, where our family generally spends a few days each year on vacation getaways. The Yachats area also features a number of other mostly hidden treasures: there's a small botanical garden along a spring-fed creek near the border of Siuslaw National Forest which is free to access, and considerable history as well. Chinook Indians frequented the area in season, harvesting sea smelt at what is now called "Smelt Sands Beach" in the state park there; they also harvested volumes of mussels that cover the easily-accessed rocks there. Middens primarily containing discarded mussel shells can still be seen along the cliffs.