My suggestion; if she's a shape-changer, could make it psychological? The idea that she at least subconsciously THINKS it's supposed to be there, even if it's not. So her brain/body just takes that information and makes it reality.

oh thats a really good suggestion! I still gotta think on it but it would make sense on why shes got her wrist tattoo too

Going with Sanele's suggestion and the fact that she used to not be a goo, it could be from a memory prior to being a goo resurfacing once she's managed to overcome the trauma-block that had kept her from accessing details like that.

reminds me of the concept of the brain's "residual self image" in The Matrix, which explained why the characters' digital avatars looked like the real them. If she sees the scar as part of herself than her goo body might form it without thinking.

She had a goo transplant or donated some goo to save a friend!

the same reason she has tats on her arms and brown parts. Comes with the package for w/e reason

So what if the scar is from the testing her father did on her before (if the testing was done while she was a normal cat?) The scar war where whaterver allowed her to transform was pumped in or was a spot she recieved an injury from a specialized weapon/tool/hazard while her body was undergoing the process of transformation. Because of this, the injury ends up becoming a permanent pain across her transformations, a phantom pain which she has learned to supress, but still is there as she learns to control her abilities and be able to transform into creatures unique from only those she is comfortable with. Later there could be room for the scar ti begin to fade as time passes, representing her learning to better control her form and the psrts of her powers that perpetuate that phantom pain, and symbolically her moving on a past the injuries of her past.

Or if now represents her already far along in that stage, the scar could originally have been much bigger beforehand, representing a grevious injury that she got before getting her powers and a nasty scar on her leg being her powers translating that phantom pain. Over time she has grown more mature and has taken to both accepting and holding control of her powers, allowing the her to ease the pain and scar tbat comes with it across transformations, until that phantom pain is little more than the small scsr we see at the present, representing how she's grown in her abilities and how the scars from her past have begun to fade.



Sorry for the long one, I find this kinda thing interesting!

TL:DR; The scar is her body, mind, and powers unconciously representing phantom pains caused by a leg injury recieved before/early-on-in the time she recieved her powers. A severe scar fading into this one may represent her character growth begging to heal from, overcome, and grow from past injuries and truamas, and her having more control over her powers to be able to supress the PAIN.

Maybe something shes effected by? Like vampires and holy items, what about salt or bleach scaring? P:

She attempted to style slide on her knees on asphalt and bears the scars with mixed pride and reminder that.

She tried it.

It didn't work.

I'd just say it was for the same reason as the IRL reason but that's just me. 👀

Just because she's goo doesn't mean they can't be 'injured' I guess? Unless in your lore they can't be 'injured'.

Tried the more common mortal body and all, unfortunately a injury happened so decided to return to normal. Scar from previous form stays on other forms.

Well, her genetics are scrambled, might be just a random effect from the DNA.
Or could be an old scar from when she wasent a goo, but stayed with her when she turned goo.