One great white shark is terrifying enough, but when a large group of the otherwise solitary hunters all go to meet at a seemingly random spot in the middle of the ocean, for reasons that are a near complete mystery, it’s a fascinating nightmare. 

The great white shark population off the coast of California mainly hunts relatively close to the shore, sticking to themselves and doing what great whites do: eat and sow terror. But once a year, a majority of the population migrates away from their regular hunting grounds on a sort of monster vacation. Roughly 20 percent of the sharks head over to the waters around Hawaii, and the remainder head out to a seeming dead spot in the middle of the Pacific Ocean. Nicknamed the “Great White Cafe” by the marine researchers who discovered the strange behavior, the reason the sharks go there is still almost a complete mystery. 

The cafe, also called the Shared Offshore Foraging Area (SOFA), is located in a portion of the ocean that is the watery version of an arid wasteland, with almost no prey to attract the sharks, so their attraction to it is bizarre. A few theories about why the great white sharks get together at the cafe have come to the fore, however. The most likely reason behind the migration is that the beasts swim out to the middle of the ocean to have shark sex. Observing their behavior in the cafe is difficult, not just because of the remote location of the meet-up, but also because while they are there, they tend to dive thousands of feet down at regular intervals. Again, scientists have no idea why. Another, more nightmarish, possibility is that the sharks head out to the location to feast on the elusive giant squid. It’s an outside possibility, but if great white sharks are hunting giant squid… the ocean may be more horrifying than previously thought.

When the great whites are finished with their mysterious business in the cafe, they return to their hunting grounds, their secrets intact. As if the sharks were not scary enough, now they can add “acting shady” to their résumé of horrors.