Planet Carboniferous

Imagine a planet where a single match can start a huge explosion due to a huge concentration of Oxygen in the air. 
HUGE insects crawl all over the planet, growing to giant sizes from the extra Oxygen, killer dragonflies hunt anything up to the size of a cat, and giant millipedes and scorpions patrol the thick, creepy swamp forests. The planet's moon is much closer, and there's still a ring left from when it formed. A day is only 22 hours long, but even in this time huge tracts of forest can be flooded by water, filled with giant slimy amphibians - the top predators of this alien world!

Well guess what - that planet is REAL. We're living on it! That planet was Earth 300 million years ago, the Carboniferous period. Prehistory is f*cking awesome XD