I heard from a untrusted source of some sort, that Super Galaxy Annie was meant to be an Ultimate skin.
They said the concept was scrapped before it could even hit PBE, due to Kai'sa's development and how it would further delay the other Super Galaxy skins. ( Nidalee, Elise, Gnar. )
Super Galaxy Annie was meant to be able to customize how Tibbers looks on summon at the fountain, and even herself; as well as changing the effects of her abilities.
She had four color schemes which were also selectable on Tibbers.
Super Galaxy Rumble's color scheme, Super Galaxy Fizz's color scheme, Super Galaxy Annie ( Base Color ), and Super Galaxy Elise's color scheme.
It was scrapped and dumped for a reason no-one knows yet, and after the Annie Ultimate skin idea was dumped; they swiftly used the same mechanics to make Gun Goddess Miss Fortune.
With almost an identical bodysuit, nearly identical color schemes and the almost 'chroma' selection method.
But again, this is just a rumor passed from one guy to another guy to another guy to another guy to my friend to me.
So take all of this with a Yasuo's side of salt.
However if this is true, they denied Annie an Ultimate skin for some reason.
( Additionally, what even pieces this more together is her splash art; with her selecting a Tibbers. )