Batman's usage of the cape as a mode of transportation differed over the years. A hang-glider version of this concept was presented in "Batman Returns", in which a harness folds out of the cape to make it a rigid wing-like structure, then folds back when the wearer rolls forward on the ground after landing. In the show "Justice League" Batman ejected from the Batplane with his cape acting as a parachute using a harness. In the 2005 film "Batman Begins", the cape was also used as a sort of wingsuit; when an electric current was applied to the cape, the shape-memory fibers (much like Shape memory polymer) aligned into a semi-rigid form resembling a bat's wings, allowing Batman to glide over the streets and rooftops of Gotham. After Dick Grayson took over the identity of Batman, he and Damian Wayne, the new Robin and Bruce Wayne's biological son, developed a "para-cape" for their costumes which gives them an ability to glide. However, at the beginning, Grayson finds that the new cape has too much weight. The also gave Batman the same gliding ability as in "Batman Begins".