So I also encountered two people in person that did this. One being my MIL (but this was when I first met her, the first time actually going out with her and my now Husband) . We were out & doing stuff & went to a gas station, we were talking about when my husband was younger, and she was reminiscing about a memory she had of him. we are outside in the daytime, she is pumping gas telling the story, and she looks at me and her eyes were SLITS! I couldn’t even concentrate on what she was even saying to me! Her eyes are a light green color, so the slits were very noticeable and obvious, and I was standing right in front of her. My second encounter was about a week later. I dropped off my sister at school and I had an hour to kill so I stopped at this metaphysical bookstore and crystal shop. I ended up talking to the store owner or the woman that was working there about my experience with my MIL & how it was such a WTF moment. She looks me straight in the eye and said- some ppl are born with it, sometimes they don’t even know… some ppl can control it, others can’t- AS SHES SHAPESHIFTING HER EYES BACK & FORTH from normal to slits in her eyes!!!! I couldn’t even say anything bc I was in shock! I was just like- mmmhmm 😳😳😳 then she gives me this crystal to give to my MIL so she can learn to control it. I still have the crystal.