Through as-yet unknown circumstances, Rebecca manifested her mutant ability. After she almost killed a teacher, her parents called Sentinel Services, who locked Rebecca up and "treated" her at a mental hospital. The Inner Circle broke in specifically to free her. Rebecca was initially reluctant to engage with anyone, but Andy Strucker eventually convinced her to help the Inner Circle simply by treating her as a normal person.
Rebecca has the mutant ability to turn objects (and presumably people) "inside out". She can literally "twist" an object through concentration and the use of spatial warps, similarly to how Clarice creates warp gates. The spatial warps let Rebecca reversing the inside and outside of any object, from pancakes to cars to human beings. Her power is limited to line-of-sight, and requires more concentration and extensive hand gestures the larger and heavier the object is. Rebecca can use her powers on a flat surface, placing anything written on it on the other side. Keeping her in darkness and constant darkness can prevent her from using her powers.
The Inner Circle rescues Rebecca from the mental hospital and ask her to help them break into Trask Financial. She does so but kills the human employees when Reeva wanted them left alive. Reeva subsequently imprisons her but Andy uses his power to free her. Rather than flee, Rebecca insists on destroying the Inner Circle. Rather than see them dead, Andy uses his power on Rebecca, killing her.
