OK, so given the nature of this trick, you could use it for anything. Pictures of whales. Or Sealab. But the post in question used it for the first BioShock, and that's about the best use I can think of.
Reddit user supergalacticcaptain posted it over the weekend, with simple instructions: you stare at the GIF above for at least 30 seconds, then look at the screenshots below.
It's like you're there, man. Only without the actual water. Or crazy undersea masquerade mutants.