History
The Mighty Oak was an oak tree that was the target of an atomic test, which mutated it, giving it self-awareness, telepathy, and the ability to move by lifting its roots. It took it upon itself to spread its acorns across the world in order to grow an army of oak trees with similar powers, and then centuries in the future, overthrow humanity and govern Earth 'without greed, without jealousy, without violence'.
Unknown to the oak tree, this was the very reason it had been targeted by the atomic test, as the scientists who oversaw the test also believed oak trees would be better stewards of the Earth than violent humans.[1]