For context I've had this rescue cat, Luna for nearly 5 years now. Raised her from 8ish weeks and she was extremely social and friendly until about 2 1/2-3 years ago. Since then she was very shut down and avoided us at all costs, though still affectionate when she wanted it. She stopped grooming herself and we had to brush her weekly otherwise her coat would get very matted. She's a domestic medium coat. (First 2 pics are post shave, 3rd is at her worst, and the last 2 are before she got goofy)

Fast forward to almost a year ago, I brought home kittens who unfortunately had fleas. We thought we got rid of them all but Luna went unnoticed and she became infested with them. I treated her for a few days but ultimately decided it was best to shave her because of the matting and also for the fleas. 

Since then she has completely done a 180. She comes up to us, sleeps with us almost every night, and even gives the dog attitude (who she was previously deathly afraid of). I've also noticed since then I haven't had to brush her once, she's completely matt free. Once her coat grew back I noticed she still had some prickly furs that hadn't grown back yet, probably her undercoat. 

Has anyone heard of anything like this before or would know what happened? It was super strange but honestly I'm glad it happened. She hasn't been this active and social in a very long time. She is a medical anomaly among other things so I wouldn't be surprised if it was just another mystery about her. I say we factory reset her 😂

Total behavioral and coat change after shave.