Inspired by the "flying ing cache" from Metroid Prime 2.

I want a creature that's maybe tripedal, with long dangly legs, with either an egg shaped body, or perhaps... I'm not precisely sure. But, something crawling or flying.

Idea: there's crystals with necromancy energy. When pressed into a person, it binds with them. The shadow magic from the crystal shifts into their body (replacing the soul), and the soul shifts into the gem (replacing the shadow magic).

They are just a vessel at that point. A zombie of sorts, but save-able.

On the Shadowfell, this cache creature finds their soul and stashes it inside. It has to stay a certain distance from the host on the material plane (so the host and creature are tied to the same relative place somewhat).

I'm not sure what combat capabilities it would have, if at all. I'm not sure it's even necessary, as, like the ing cache, it's purpose is just to store.

I'm curious what you'd come up with though, if anything.