Still awake, so here's the other story:
According to the John Day Fossil Center, starting many millions of years ago, Northeast Oregon was regularly destroyed by enormous volcanic eruptions. From these would flow Old Testament style rivers of mud and lava, smothering everything living under thick sheets of burning rock.
This would happen every 5-10 million years, and after each apocalypse, animal and plant life would gradually return. Because the eruptions were spaced so far apart, the climate would be slightly different each time life reappeared, and the species that returned would also be different. Some would be new species, some would return changed, having evolved in the interim, and some species would never return, having gone extinct.
One of the returners was Oreocyn. These were a kind of carnivorous pig-hyena, big brained and graceful, one of the area's most successful hunters. They were also unrelated to any other species, prehistoric or modern. A paleontological mystery.
After every eruption, Oreocyn would return and thrive for a few more million years, adapting to the new environment. Sometimes it would come back with longer legs, next time an extra toe, or a different diet, whatever the new situation required.
Then after one eruption, it didn't come back. It disapeared from the earth, leaving no descendants.
All this exists only as bone fragments embedded in stone. Isn't that amazing?