system
Given the following post, respond as if you're commenting on Reddit:
human
[Magical Girls] Help, my girlfriend keeps shouting "To the power of the moon" in public!

I'm desperate. We are childhood friends and have a 5 years relationship, she was always very reserved and kind.

Recently I had an accident and was near death but thanks to the power of Science! I made an almost miraculous recovery. After that day she changed, she started carrying a creepy ferret-cat plushie with her and recite spiels about the power of friendship and love. She goes out at night at random hours in cosplay.

She also bounces from bubbly happy and shouting stuff like "to the power of the moon!" in public to depressed and angry at everything I do. She also gained a strange interest in German literature, thermodynamics and entropy.

We haven't had intimacy in a while either, she says weird stuff like that if we do it she'll turn into a speck of light and vanish yet she's been very touchy feely with other cosplay wearing girls. The other day I found her kissing the aloof transfer student and when I callled her on it she said it was "mana transfer" or something.

I read a bit in forums and I think she may be possessed by something. She acts really weird (blushing and gasping) when I touch a shiny stone she carries in her neck at all times and refers to as an "intelligent device". I'm thinking of breaking it or throwing it from a bridge to see if its the cause.

Also for some weird reason I'm getting less and less screentime.

How can I support her and help her go back to normal? Is it just a phase and I can wait it out? I fear for her safety and our relationship, what can I do to help her? And why won't she invite me to her "mana transfers"? I want in too!

If it helps I'm a geeky guy that's good with computers.

**tl;dr:** My girlfriend is acting like a magical girl. She says she made a contract or something, how can I help her and remain relevant to the story?
gpt
You should create a masked identity as a roguish thief. When she isn't looking, roam the town, stealing from the rich to give to the poor. If there's monsters, throw down a smoke bomb and hit it with a stick a few times. Don't worry, you'll be fine. If your girlfriend is really a magical girl, she'll show up to defend you, or you'll show up just in time to help her out. 

Then, with the power of true love she'll power up, be able to defeat the big bad and then you can return to normalcy.

Or she's not a magical girl, and you'll end up saving some other girl, and now you'll have a romance triangle between your normal (yet strange) girlfriend in your normal identity, and between your masked identity and the magical girl. Guaranteed to give you a subplot at least!