Shadow Imitation can easily chase down a target and relocate itself. But, once the Shadow Covers an area, the tendrils are summoned through it. Once tendrils are summoned, they cannot move. You can summon more, but they can't "shift" from their spot. I know it sounds like a tiny things, but I literally have had people chase down others with tendrils that are basically intangible, regrowing bits of blackness. It's a bit broken. So, for that purpose, I break it down into two steps: Placement of the Shadow, then creation of the tendrils.