Charizard has only two forms. Normal form and Shiny form. In Normal form it's body colour is reddish orange with a red fiery tail. In Shiny form it's body colour is grey with a blue fiery tail. Did you see it when it's body colour was reddish orange with a blue fiery tail? If you did, it was probably an illusion cause' it's impossable. It's one or the other. And Blaze doesn't change the image of a Pokemon, it only boosts your Pokemon's Fire-type moves when it's health is red.
Hope this helps