You a speedster were running you did not notice but you traveled back in time. So you went back to STAR Labs because you had to return the suit before going home you walked into the Cortex to find your in the past Cisco: who are you?

Caitlin: and how did you get in here?

Barry stares at you noticing the features that you two share. But you can't tell him or you could change the future and cease to exist.