Unlike most elastic characters, Bungee requires a force to stretch. This means that she would either have to "throw" her arm forward to stretch it instead of just letting it extend. It also means that she can be stretched or reformed, but only very roughly and only through an external force.
Not much is known about Bungee, and even if something was known it would only scratch the surface. She doesn't let anyone look at her, let alone see most of her face, to prevent them identifying her; and the only people who have seen her were either a superhero or just caught a glimpse of her. What is known are that she primarily wears black and red, has long red hair tied by a large shuriken, and she likes caramel and cosplaying.
Bungee, as she only works alone in mysterious ways, does not have any known allies