The Japanese name for Diancie and the Cocoon of Destruction is The Cocoon of Destruction and Diancie (Hakai no Mayu to Diancie)
For those who don't know, Meteor Shower at Dawn (夜明けの流星群 Yoake no Ryuuseigun and can also be translated as
Dawn of the Meteor Shower, which in my opinion sounds a lot more epic) is the song for Diancie and the Cocoon of Destruction. You can listen to it
link, but it's only in Japanese.
Of course Meteor Shower at Dawn might not be the English name. Japanese Pokémon movie songs tend to be named after the first words in the song, and one of the first words is
yoake (dawn). But as many of us know English songs aren't usually like that.
Lyrics:
Yoake mae fukiareta kaze wa nanno maebure?...
