Megalodon did not "form" in the sense of being artificially created. It was a naturally evolved species of shark that developed and thrived during its time. Like all other species, Megalodon's existence and characteristics were shaped through the processes of natural selection and adaptation to its environment over millions of years.
Megalodon evolved from smaller ancestors within the Otodus genus. Over time, certain species within this lineage experienced advantageous genetic mutations that allowed them to grow larger in size and develop stronger jaws and teeth, resulting in the emergence of Megalodon. The availability of abundant prey and the environmental conditions during the Miocene and Pliocene epochs also contributed to the success and dominance of Megalodon in its ecosystem.