That was almost a form of alchemy, where it changed him into The Flash.
I’m really excited about Doctor Alchemy because we haven’t had someone who’s an alchemist.
The idea that one thing, X, can be changed and turned into another, Y. Unfortunately, Helbing didn’t provide any specific details about the show’s Doctor Alchemy, including which version of the character will be under the mask.
The producer’s comments also seem to hint at “transmutation” being a recurring theme throughout The Flash Season 3, not just with Barry and Alchemy, but with the other metahumans and probably even the non-powered characters.