I need help identifying this wire (chewed by rats)
 

Hi, I have a 2013 86 and not really well versed with electrical wirings. As i was cleaning the engine bay i noticed a wire that had a portion of it was exposed(probably chewed on by rats). Can anyone tell me what wire this is. Thank you

Looks like a ground wire to me and it looks normal.

Here is a look at the other side which has a portion of it exposed

Looks like there's enough there to cut, terminate a new ring terminal on and bolt it back up.

That looks more like abrasion. No tooth marks like a miniature beaver tree.
It's a dedicated ground wire and still solidly attached to the block. There won't be sparks escaping.
A little insulating tape will take care of it sufficiently.
Bend it up a bit more so it won't keep sanding itself off in future.

This ^
As long as the wires themselves are intact all is good in the world.

Wrap it with a few turns of silicone rescue tape. If you've never used it, prepare to be amazed.
For best results, wash your hands before activating (stretching), and wrapping it.