Kayla

Kayla (aka 404) is a character originated on Pixilart on this specific drawing: https://www.pixilart.com/art/best-friends-95388e9fe0da134?ft=album&ft_id=48881

Kayla is a ghost type Eevee who haunts Lizz, she is unaware where she came from and why she's haunting her but she's trying to get rid of her. When she was killed by Shadow Eevee, Shadow Eevee mysteriously disappeared, and so did Kayla.... But not for long.. She apparently came back, and got the revenge she has waiting for: She created a series of odd pixel artwork, some with strange binary in the description, or the title. ...We have NOT heard from Shadow Eevee, or Kayla ever since last year.. (2019)

That sounds like good news for Lizz!