That’s a Mola mola, a bizarre ocean sunfish that’s becoming a common sight in California waters.
Molas are huge, obviously – its size relative to the human diver isn’t a photographic trick. And they’re weird-looking. The one Botelho shot looks like a moon or a flattened Sprite can. Molas are the heaviest bony fish in the world, weighing an average of 2,200 pounds. Despite their bulk, they’re rather peckish; their mouths are relatively tiny, and they live primarily on jellyfish.
Botelho’s photo is a rare image of a mola in its natural environment. Apparently they’re skittish; they don’t like to be around humans. This one lingered long enough for Botelho to capture the amazing image above … which he mistakenly slipped into a folder of photos he didn’t intend to use.