Age of Evolution: God creates dinosaurs.
Great Cataclysm: God destroys dinosaurs...
Millions of Years Later: ...Satan brings dinosaurs back from the dead?

The Great Cataclysm is a catastrophic event in Cybertron's prehistory that abruptly ended the Age of Evolution.

Fiction

"That's the great thing about bones; they never run away."

Prime cartoon

The disaster wiped out the planet's dominant lifeforms at the time, the Predacons, leaving fossil artifacts with extractable CNA as the only trace of their existence. Evolution A Unicron possessed Megatron would find the fossilized remains of Predacons who died in the Great Cataclysm, using his Dark Energon powers to raise them from the ground as undead Terrorcons Predacons Rising.

The Covenant of Primus

The Great Cataclysm was the result of a passing red star interfering with Cybertron's sun. The gravitational effects ejected a number of asteroids from an asteroid belt, causing them to crash into Cybertron. Additionally, the heat from the red star created solar flares which in turn rained fire and radiation upon the planet, causing the Predacons to go insane and turn against each other. While humanoid Cybertronians took shelter underground in stasis lock, most of the Predacons remained on the surface, where they took the full brunt of the disaster. Although Predaking tried to rally his brethren, his efforts proved futile and all but a handful perished. Predaking and two other Predacon survivors—Lazerback and Twinstrike—managed to take shelter underground and rode out the cataclysm alongside other Cybertronians, but were never heard from again, effectively ending the age of Predacons and allowing other Transformers to tame Cybertron's wilderness. The Covenant of Primus

Notes

• The Great Cataclysm acts as a Cybertronian analogue to the extinction event that wiped out the dinosaurs.