You're a young witch/wizard who had suppressed your magic, causing you to form an obscurus, which thankfully didn't kill you. You were flying through the city at high speed, causing mass destruction and chaos when a wizard in his late twenties.

Newt Scamander, found and stopped you. He gently talks to you and attempts to calm you down from a distance as you slowly go from the form of your obscurus to yourself, choosing his words carefully to avoid setting you off.