Possessed Janna
This idea is sort of a tribute to Storm from the X-men series, but basically Janna looks possesed.
Her skills change, starting with her auto attacks being Lightning bolts.
Her Q tornado looks darker and has lightning sparks flying around it
Her W shield now looks more like a cylinder of wind around the target
Her E slow would now be basically a darker cloud but the effected enemy would be zapped by lightning from the cloud
and her Ultimate would basically look the same however Janna would look boss casting it.