Ant-Man is a legacy super-hero name, primarily associated with the ability to shrink in size. The original was Hank Pym; he was a founding member of the Avengers. Scott Lang took the name, an ex-con who broke into the New Jersey home of Dr. Henry Pym, and stole the Ant-Man's Suit. Lang has been a member of the Avengers, Fantastic Four and Future Foundation. Eric O'Grady took the mantle until his death.
Dr. Henry "Hank" Pym