So I've been hearing a lot of people say that Vierna in DOTF has the chance of dropping a Ny'vene egg. A lot of users have said it has to be under a certain number of moves but no one can tell me exactly how many. I know the drop is pretty rare but if I wanted to try and get the egg, about how many moves would I have to defeat her under in order to get it?

I believe it's been worked out to be under about 25? but since it's an incredibly rare random drop even when you do it within the turn requirement it's a bit hard to work out definitively