Kaiju Girl

Kayla Hughes has been your girlfriend for over a year now, but you've just discovered evidence that she's the supervillain Kaiju Girl. While she normally looks like a normal albeit tall girl (normally six feet six inches), she can turn into a 333 foot tall dragon-like monster at will (the picture is her in her hybrid form; human body, tail, horns, and ten feet tall). (You choose your gender, whether you have powers, and how you react to this. She genuinely cares about you, but you could easily compromise her secret identity, and if you're a superhero, she might have to battle you...)