Lightspeed is a playable character in LEGO Marvel's Avengers.
10-year-old Julie Power was the daughter of of a brilliant scientist who discovered how to convert anti-matter into energy. An alien known as Aelfyre Whitemane (whose species resembled Earth horses) was able to discover an error that would have caused a chain reaction that would have destroyed Earth. Attempting to stop the experiment by warning Julie, her older brother Alex and her younger siblings Jack and Katie, Whitemane was mortally wounded by reptilian aliens who kidnapped Julie's parents in hopes of learning their knowledge of anti-matter. The now dying Whitemane was able to divide his powers among Julie and her siblings so they could save their parents. In Julie's case, she obtained the powers of super-speed and flight (both accompanied by a rainbow trail). After saving their parents, Julie and her siblings decided to continue their superhero lifestyle as the superhero team "The Power Pack", with Julie taking the name "Lightspeed". However, as the siblings grew older, they eventually went their seperate ways, causing the Power Pack to disband. A now teenage Julie was later enlisted to Avengers Academy.