Here’s a thing for you:

Exploding lakes. It’s true. Lakes can explode. It happened in Cameroon, which, if you don’t know, is a country in Africa. No one knew it could happen. Not even the Scientists. Everyone’s been walking around lakes this whole time, the whole of earth’s history, thinking, “Well, at least that huge mass of water won’t erupt and drown who it can and asphyxiate the rest in a cloud of CO2.” Think again, population of earth, particularly inhabitants of Northwest Africa. Some lakes have gone bad. Some lakes are bad apples. Some lakes lie in wait, wind just shimmering across the surface, spirit on the face of the deep, spirit under the face of the deep, and after thousands of years, once everyone’s sure they won’t, they leap out and grab you. Or you’re sitting at home, ten miles away and suddenly you can’t breathe, and you suffocate in your home, knitting, or reading, or collecting firewood, or whatever people in Cameroon were doing in 1986 when Lake Nyos exploded and a cloud of CO2 spread over 16 miles of land and suffocated 1700 people.

Let’s say there are these two guys, Cameroonian farmers. They live close to the lake, but don’t know (no one does) that way down below the lake, some slow volcanic process is releasing CO2 into the cold water at the bottom of the lake, which is fine, as long as nothing disrupts it. As long as everything stays exactly like it is. One of them is afraid of the lake. His name is Joseph. The other loves the lake. His name is Gregory. They don’t really know each other, but Joseph has watched Gregory enjoying the lake, swimming, diving, in love with the way that water makes the human body capable of flight. But Joseph has also seen the terrible power of water. The lake—let’s assume, because of its close relationship with the Oku Volcanic Field—has been bitch to occasional seismic or volcanic activities. These have produced large waves from time to time. When Joseph was five years old, still just a wader, he saw three cows and a favorite dog swallowed up, crushed, and otherwise drowned by a 20 foot wave that rose like a whale from the center of the lake. He has undiagnosed PTSD (it’s the 1980s, in Cameroon; all PTSD is undiagnosed), and can’t handle the lake.

Gregory spends every day he can in the water. Friends and family have told him that his mother must have mated with a fish. Sometimes Gregory wonders. His skin is mottled in a peculiar pattern along one side of his rib cage, it reminds him of scales. He loves the water. Though neither of them remember it, Gregory was near Joseph for the wave, but, being a strong swimmer even at the age of seven, was caught up further out in the water, and rode on top of it. He felt the power of water too, but, as he emerged without injury, felt that he controlled it, could handle it.

But then here’s August 21st, 1986. Joseph has attempted to face his fears many times, but today will be the day. He’s at the water. Of course Gregory is at the water. It’s practically all he ever does! He’s developed this method of swimming and fishing at the same time. He can swim on his back, cast and reel and haul, the whole thing, just bobbing around like a clawless otter.

But as Joseph approaches the water, determined, the water at the center of the lake begins to froth and bubble. He watches for a minute. It’s bubbling more vigorously. Well, he thinks, that’s a sign. All it takes for him to not go back in the water is some bubbles. He gets on his motorcycle and rides listlessly away from the lake, then hears the boom. He stops his bike. And turns around. He’s still in sight of the lake and can see an enormous tidal wave swelling. He makes out a figure on top of the wave. This causes him to take a sharp breath. But then he smells a horrible smell. He tries to call out but can’t. He doesn’t know it, but his lungs have entirely filled with CO2. Joseph lies down.

On top of the wave Gregory can’t believe what he’s summoned. He’s 80 feet up, and moving fast for the mainland. He knows there’s no way out, and that nothing good will come of riding a wave as big as a god to the shore, but Gregory is smiling.