That’s a whale of some sort, clearly, a baleen (filter-feeding) whale. If you watch, there’s a ring of bubbles that pops up shortly before the whale does. That’s a bubble net, a ring blown by the whale to herd the small fish into a school. Going by that, it’s a humpback whale. They’re more predatory than other baleen whales, going after larger fish and intentionally corraling them, but still only eat small fish. You can see all the little fish jumping when the whale comes up- those are what it’s after.

if you managed to get yourself into the whale’s mouth, it would open its mouth and let you out. Their throats are only about as big around as an orange, they can’t swallow you. Unlucky birds, sure, but not humans. They occasionally catch sea lions by mistake and just spit them out.

In short, the maw rising from the water to engulf several thousand fish is horrifying, but harmless.