Watch A Terrifying Giant Fish Swallow A Shark Whole

A group of fishermen hooked a four foot blacktip shark off the coast of Bonita Springs, Florida this month - but they didn't expect what happened next.

Sharks aren't the biggest creatures in the sea, but usually we think they're only at risk of being attacked by people or other, bigger sharks.

But sharks are just fish too, and as the saying goes, there's always a bigger fish.

One of those fish is the goliath grouper, a monster of a sea bass that can weigh as much as 800 pounds. You can see one lurking around the boat right at the beginning of the video.

As the fishermen start to pull the shark, who was already having a bad day, out of the water, the grouper spots an opportunity, and lunges for a bite.

Goliath grouper have been known to stalk and try to ambush divers as well, according to the University of Florida. So the next time you're deep underwater and a giant boulder seems to be moving towards you, be aware. Here's what to watch for:

Watching the video for the guy's reaction at the end is highly recommended: