In a clip from the BBC's Blue Planet II, we get a look at that last scenario and what happens when a few researchers accidentally interrupt lunchtime in shark city.
The Blue Planet team dove more than 2,200 feet below the ocean's surface to "discover what happens to a whale carcass on the seabed," but they had no idea what to expect. The first thing you see in the video is their submarine passing through what looks like a dust cloud and the team immediately knows something is up. Through the dust, you can just make out a shark swimming slowly by.
"Ay yi yi yi yi, that's a big shark," someone says.
Then the video gets really good. The submarine approaches a whale carcass and you can see several sharks swimming around it, feeding on it.
"I've never seen anything like this. This is unbelievable," a woman aboard the sub says.
But what happens when the sharks spot their onlookers? Well, they get aggressive as you might expect.
The people in the submarine (and us, watching this video) are suddenly treated to an up close and very personal look at these hungry sharks as the creatures mistake the vessel for competition.
The sharks start to mash their heads against the front of the submarine, pushing it and hitting it over and over again.
"The submarine is very strong, but they're so big and strong that I'm a little bit afraid," one man says as the shark attack continues.
Fortunately, everyone aboard was fine, and the sharks soon realized the giant metal ship was not trying to steal their lunch.