>>50500045Shiny Nihilego saved Mohn and he thought it was Lillie after losing his memory. That scene is at the end where the real Lillie and her family accept it as a new member of their family, essentially humanizing the species that has been a monster plaguing their family for all their lives, and symbolically overcoming the trauma that split them apart. It's very moving and even the light streaming in represents that the outside world Nihilego has been hiding from is actually warm and inviting, contrast to the dim shack it's been living in for all these years.