Based on this prompt from fandom-queen-supreme on Tumblr: "Winter Soldier AU Olicity"
I cheated a bit here. Let's pretend that the AU is that Oliver gets revived in the Lazarus Pit by Ra's and, as comic book lore dictates, goes a little nutty after. Also, Felicity isn't a superhuman. Everything else pretty much applies.
Felicity would know that physique anywhere. She's seen it in all sorts of clothes–suits, leather vigilante costumes, casual wear, no shirt–but she doesn't believe its Oliver under that League get-up, holding a sword to Diggle's throat, until she sees him pull of the mask.
She experiences a million emotions in a matter of seconds. Joy that he's alive, confusion at how that could be true and finally terror when she notices the hard look on his face, void of recognition or kindness.
"Oliver?" she sobs, desperate and terrified. His eyes narrow, a momentary look of confusion flashing across his features before that murderous glare returns.
"Who's Oliver?" he asks. Felicity screams and she's thankful for the blow to the back of her head that knocks her unconscious.