I hoped you saved before approaching the boss level.
No, this is not an amazingly hi-res preview of a boss enemy in a new Metroid game, it (terrifyingly) is real life. This video was taken by snorkeler Jonathan Gordon, who wrote,
This guy took me completely by surprise while snorkeling in the Caribbean. I dove down to have a look at the shell that you can see just under where the octopus appears and as I approached the octopus came out of hiding. I had literally no idea he was there until I was about a metre away.
Usually, humans like to tell themselves that threatening animals are more scared of us than we are of them. I don't think this 'pus is scared. I think that 'pus is enraged. Leave that 'pus's shell alone, dude.
How the hell does that even work?
When it comes to animal camo, octopi make chameleons look like 80s skiiers wearing DayGlo in the snow. Check out this SciShow video on how the wriggly invertebrates put Pentagon technology to shame: