"The original DNA was thought to be too damaged to use, but one scientist found a way to restore it, thus came the creation of Regigigas. At first, all attempts to revive the monolith were failures. Assumed inactivatable, the giant was left to gather dust&plants began to grow on it. It was only when the three other golems were awakened that the goliath began to stur. No one was to know of the danger when these Pokemon were let loose from their hibernation. Another facility had been working on similar projects using DNA but something gone wrong; an extremely powerful creature escaped, being bred from an ancient Pokemon found in distant ruins. The trio were released to stop this monster but it mysteriously vanished. No one bothered to check Regigigas, and it was too late. It had unspeakable power, tearing across the land&destroying anything in its path. The army threw the best it had at them but it was no use. They rained havok down upon the cities they trudged through until the fourth day when they suddenly stopped. They locked ‘em away deep underground; they couldn’t be annihilated, so we just prayed they will never wake up again."
Day of Reckoning, by Joshua Dunlop.