Ultimate Marvel: Earth-2/Cassandra Lang

Ant-Girl (Cassandra "Cassie" Lang) is a fictional major character and superheroine appearing in Ultimate Marvel: Earth-2.

Early life
Cassie was born in Brookyln, New York City, raised by her parents Scott Lang and Hope Van Dyne. She grew up living life like any ordinary child, but displaying a great admiration for superheroes. This motivated her parents to become superheroes themselves by donning their versions of Hank Pym's Pym Particle suits (with Scott becoming the new Ant-Man after Hank Pym and Hope becoming the Dragonfly).

Becoming Ant-Girl
After enjoying her 10-year birthday party (which was also attended to by Spider-Man as a special guest), Cassie had a moment with her father at night. From Scott, she earned one last special gift: a Nanotech wrist device containing Pym Particles. Excited and grateful, Cassie vowed to do what must be done to be a heroine like her parents and other known heroes in the world.

Next day, she soon designed her suit through the device's pannels and begun her career as Ant-Girl. Starting with simple civilian acts, Cassie soon begun to take on her first foe: the outlaw Whirlwind, who was at the time robbing from Roxxon and bullying J. Jonah Jameson's son Rowley (also known by public as the superhero-wannabe Captain Ultra). While Whirlwind was taking on Captain Ultra pretty easily, Ant-Girl shrunk through Whirlwind's armor and begun attacking his soft skin, with Whirlwind just screaming in pain, not knowing what hit him until Cassie ejected from his suit and revealed herself.

Just as Whirlwind teased that she would not stop a bomb which he implanted beneath a nearby school with children and pulled its trigger, Ant-Girl just replied she already took care of that; she had found and shrunk the bomb into miniature portions and hidden it inside Whirlwind's pants. The bomb soon exploded and caused great pain in Whirlwind's groin as he screamed like a girl to both Ant-Girl and the crowd's amusement. Ant-Girl soon earned the appretiation of the citizens (including her parents, who were watching from the distance), though Captain Ultra just felt constant humiliation of being "up-staged by a little girl". Seeing how much being a hero is very enjoyable, Cassie embraced her new calling with delight, though she also had to balance it with her normal life as a normal citizen and school student.

Along the way, she also earned herself her own arch-nemesis Yellowjacket (who happens to be Cassie's aunt Janet Van Dyne's rival in college Rita DeMara) after stopping her from demolishing a Pym Industries facility. She also had the attention and mutual respect of other young heroes such as Spider-Man and his friends. She also joined them in their training under the tutelage of hero veterans (like Shang-Chi, El Diablo, among others)