Who she is: Sydney “Syd” Barrett
Her power: Syd is a mutant. Any skin-to-skin contact with another person causes her to switch bodies with them for two hours, gaining access to any powers or abilities they might possess. After the time limit is up, Syd and the other “participant” transform back into their own bodies, but maintain their current locations.
Her story: Seen in Legion, the manifestation of Syd’s uncontrollable power causes her to develop an extreme aversion to physical contact with others, one that eventually led her to be institutionalized at the Clockworks Psychiatric Hospital with David Haller. When Haller, her boyfriend, impulsively kisses her, he and Syd switch bodies. Her access to David’s quasi-omnipotence causes massive psychic chaos, exposing both her and David to the attention of a number of clandestine groups. Recruited by members of the mutant commune at Summerland—who believed her to be David at the time—Syd eventually rescues him from government capture. Now, she resides in Summerland, helping David work through the memories and issues keeping him from controlling his powers.
Currently, Sydney Barrett is: Hanging out at Summerland, presumably wondering why David got captured by a tiny sphere.
Where will we see her next? On the second season of Legion on FX.