I sort of have mixed feelings about Ash/Greninja requiring a Mega Stone because I thought it would be something unique and in a category of its own, but whatever.

And, Serena's face. BTW, as stated in the caption, Bonnie and Clemont have gone out somewhere to buy medicine, while Serena watches over Ash.

But look at her face.. It looks like she's witnessing Ash slowly dying and she's confessing her feelings tbh xD