It may appear quite captivating, but what follows the bubbles would make any sane person run for cover.

You won’t want to see those bubbles in the middle of the night, I can assure you.

What do they signify, then?

The terrifying implication is that you and everything in the circles will be completely engulfed by enormous humpback whales.

This is because it’s their unique hunting technique, as a commenter pointed out: “This is called Bubble Net Feeding, a hunting technique used by whales. They blow bubbles as they spiral around fish, trapping them in a tightening circle. Then they surge from below to gorge on them.”

Another wrote, “Those are humpback whales, I think – they are lunge feeders.”

According to the National Marine Sanctuary Foundation, a pod of whales use a cooperative hunting technique called bubble net feeding.

Each whale