Well this is likely to be scrapped, as it was my original idea in progress since I made the Onem ages ago. In short it's their second phase, once their bodies built up enough energy they enter a caccoon and emerge like this. The top left pose doesn't work so well.

The body form was built using body forms like Blazin' Flizard and Fenri Lunaedge from the Megaman Zero series. However the Onem mix of reptile and fox traits, and a certain new pokemon... make me wish I had done this sooner since I know people are going to think I'm just trying to copy from that.
But just like the origin of the Onem... I was copying from MEGAMAN sprites ^^;