Stage 30 causes quite a ruckus after the first few minutes. Kohaku accidentally causes Rin to bump into Shirou while projecting, causing not Kanesada to be projected, but instead Magical Ruby, which manipulates Rin to transform into Magical Girl Kaleido Ruby. What next? Arcueid as Phantasmoon overhears Kaleido Ruby's one-liners. She then looks for better clothing, goes backstage, steals Caster's staffjust because she can, and transforms into Eclipse and proposes a duel to be the sole magical girl in the game, with enemies to deal with to see who's better. At the end of the stage, once Rin comes back home, she laments how she was welcomed with Shirou in shock and Archer laughing.
Anything with Phantasamoon. One of the most powerful vampires in the world cosplaying as a Magical Girl.