Original Description:
A full mock-up of one of the cards I made based on the Journal of the Two Sisters, with additional pyrotechnics provided by Phil Srobeighn.
For context, late in the journal, Celestia starts visibly glowing while putting the fear of herself into a dragon via Royal Canterlot Voice. She also doesn’t remember doing so afterwards. I’m not saying it was Daybreaker, but I’m not ruling her out either.