Cassie Lang suffered from a congenital heart defect at a young age. To save her life, her father, Scott Lang, stole Henry Pym's Ant-Man equipment and Pym Particles, which he uses to rescue Doctor Sondheim, the only doctor able to cure Cassie's condition, from Cross Technological Enterprises. As Cassie became older she wanted to become a hero just like her father.
With Ant-Man for a dad, Cassie was able to encounter the world's greatest heroes on a frequent basis. One night Cassie planned to leave home and join the Runaways. However, that same night Cassie learned about the Young Avengers. Intent on joining them, Cassie sought out Kate Bishop, the young woman rescued by the Young Avengers. Together the pair went to the Avengers Mansion and found the four teen boys called Iron Lad, Patriot, Hulkling and Asgardian. An argument soon erupted about Young Avengers membership, and Cassie began to grow at an alarming rate to everyone's surprise and later confided to them that she had been secretly taking Pym Particles for years. Not long after, Cassie adopted the persona of Stature, and became an original member of the Young Avengers. Currently, Cassie fights crime as Stinger and has been training with her father to better control her powers.
