And Prototaxites wasn't just confined to Canada. Fossil hunters have dug up the titanic shrooms all over the world, suggesting that it was probably the biggest life-form on land at a time when animal life was nothing but microbes and worms.

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All earthlings were giant versions of the stuff living on your bath mat.

After plants learned how to stand up for themselves and stop getting pushed around by glorified athlete's foot, they started evolving trunks and hogging the resources Prototaxites needed to grow, so plants won the race and fungi were reduced to living off their rotting garbage.

Insects today are limited in size only by the amount of oxygen they're exposed to. Our 20 to 21 percent oxygen level means that we climb onto a table if we see a cockroach any bigger than 1.5 inches. In the Carboniferous, you would have had to contend with scorpions the size of dogs, caterpillars you could mistake for anacondas, and dragonflies that could fight an albatross.

Ned Seidler/National Geographic
Dragons were named after these fuckers.

Combined with the fact that predators such as birds and reptiles were millions of years away from evolving, environmental conditions meant bugs could pretty much just grow until they reached B-movie proportions. But there was another side effect of such a high-oxygen environment -- the world was basically on fire all of the time.

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So, don't count on that flamethrower doing jack shit to save you.

Because fire is basically just what happens when you add oxygen and heat, it didn't take much to start a fire in the Carboniferous period. As a result, wildfires swept constantly across the globe, and it's speculated that smoke would have made the sky a permanent hazy brown. Picture it: Just a bunch of giant, flaming insects hurtling at you out of a blinding fog. Resident Evil was apparently historically accurate.

If you got sucked through a wormhole while piloting a space shuttle and wound up orbiting Earth 3 or 4 billion years ago, it would've looked extra fabulous. One hypothesis says that the planet would actually have been purple.

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Grimace isn't a mutant. He's a time traveler.

The reason that the land on Earth looks green from above is because of our plants, which are only green because of their chlorophyll. But plants didn't always harness chlorophyll -- back in the earliest stages of life, they used a different chemical called retinal, which is purple.

Jynto/Wiki Commons
If your own retinas are purple, you are the chosen one.

Scientists believe that, for some time, purple-colored organisms may have been so abundant on Earth that the whole place looked like Prince's home world.

Come on, you know he doesn't come from here.

The dark side has a much thicker crust and a more varied surface. If the moon hits your eye like a big pizza pie, well, the front side would be Brooklyn-style, and the rear is straight-up Chicago deep dish.

Scientists have wondered for a long time how the two halves could be so geologically different, and one theory suggests that, at some point in the distant past, the Earth actually had two moons, for a period of around 80 million years, before they got caught in each other's gravity and crashed together -- presumably while drunk.

M. Jutzi, E. Asphaug
And they've spooned ever since.

These huge impacts created enough heat to vaporize metal, such as iron, gold, and platinum, which would have ascended into the atmosphere as a kind of metal vapor. And since what goes up has to come down, the early Earth would have experienced metal rain.

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Golden showers for everyone!

Still, early life shrugged off this calamity as just another every day thing. You wake up, you eat breakfast, you lounge about for a while, you bunker down for a global extinction-level event, you have dinner, you go to bed. It kind of puts human problems in a whole new perspective.