It might seem weird to imagine a lake within the ocean, but things like temperature and salinity can change the density of water, and "lakes" of denser water can form within a larger pool. Scientists recently discovered such a lake at the bottom of the Gulf of Mexico, but this lake also has something else very strange going on: All the creatures that enter it don't come back alive, reports Seeker.

The lake, dubbed the "Jacuzzi of Despair," is about 100 feet in circumference and about 12 feet deep, and it lies on the ocean floor nearly 3,300 feet below the surface. It's littered with the dead bodies of benthic crabs, amphipods and fish that have crossed over into its waters, lured by the warmer temperature.

The super-salty brine in the lake contains four or five times more salt than the surrounding seawater, and it stews on the bottom like a thick witch's cauldron, collecting toxic chemicals such as methane and hydrogen sulfide. The lake is also connected to a brine river that actually flows over the seafloor.

“It was one of the most amazing things in the deep sea," said Erik Cordes, associate professor of biology at Temple University who discovered the site along with several colleagues. “You go down into the bottom of the ocean and you are looking at a lake or a river flowing. It feels like you are not on this world."

The waters within the pool are dammed in place by a living mat of bacteria and salt deposits. It likely formed as seawater seeped into cracks in the seabed and mixed with the region's subsurface salt formations. Methane gas then bubbled up, taking the deadly water with it.

Life is surprisingly plentiful around the lake's borders, but creatures that cross its boundary don't come back alive due to the toxic mixture. Water in the pool measures about 65 degrees Fahrenheit, which is like bathwater compared to the surrounding sea.

“If you muck around in the lake, you can make waves of brine that break on the shore," said Cordes.

The scene conjures up impressions of an alien world. In fact, researchers believe studying extreme places like the Jacuzzi of Despair can give hints about the kinds of conditions that might exist on other planets.

“There's a lot of people looking at these extreme habitats on Earth as models for what we might discover when we go to other planets," explained Cordes. “The technology development in the deep sea is definitely going to be applied to the worlds beyond our own."

For another view of brine-lake danger, see this clip from BBC's Blue Planet II: