Ant-Man has had two identities in his time in the Marvel universe: Hank Pym and Scott Lang. Ant-Man's powers consist of shrinking very small and growing very big. Hank Pym developed a serum called Pym Particles. This formula could shrink a man to the size of an ant or as tall as a building. He used this to help shield on many missions, but after his partner and wife died on one of those missions, he decided it was time to hang up the suit. After being voted out, his company was given to his protege Darren Cross / Yellowjacket / M.O.D.O.K... After Darren had discovered some of Hank's work on the Pym particles, he was desperate to replicate them and did so successfully. He was planning to sell them to Hydra. Hank would not let this happen, so he enticed Scott Lang, a burglar with a criminal record, to help him and his daughter (Hope) steal it. Lang completed this mission successfully and was dubbed the new Ant-Man. Scott would later go on many more adventures, including going to the quantum realm, helping Captain America in Civil War and kind of inventing time travel.