AU Surge has got one official transformation in LTMEA, which is the Overddrive version of herself.

(Some old pic about the transformation https://x.com/exSURGEt/status/1767304931239702656/photo/1 and https://x.com/exSURGEt/status/1741595089397530990/photo/1)

Pretty much Surge's whole body would be covered into white electricity to the point it feels like she's not tangible anymore. She gets unstable, impossible to control and its pure raw energy striking whoever gets in her way. It consumes her stamina a lot and it won't last much.
A little warning here, it may be graphic the aftermath: In my original idea of Overddrive Surge, her skin and flesh would burn away from her cybernetic endoskeleton, making her look like a very skinny android. It would take her half hour or one hour to regenerate herself back to herself.

Now I'm not sure if I'm keeping this gruesome idea for LTMEA. It is from an old draft and probably it is TOO MUCH EDGY, but I still wanted to tell this little trivia anyway. :P