I (personally) cannot bring back the Megaladon, but maybe scientists can if they can find some DNA of one. When I was in year 5/6 I was obsessed by Sharks and used to have loads of books on them. I still have a few (small) sharks teeth at home from a Hammerhead shark, it would be cool to have a Megaladon tooth on my desk!
Carcharodon megalodon is by far the coolest animal to ever have lived. He was ever bigger than the Great White (Carcharodon carcharias) Shark that was depicted in the film Jaws.