ALRIGHT. After going over both the original spells Reira had as a Wendigo and Kelpie, I think it should be fine with the same stipulations; limited mobility, max 5 minutes of length, and if she wants to use it twice she needs to feed on someone.

Beyond that, could literal shadow be an acceptable replacement, letting it double as a quick way to get into other shadows in the area and skedaddle?

If not, I'm just going with smoke! (POOF!)