Leaf bug (Phyllium giganteum)
The constant wobbling as they move is a part of their disguise, making it seem as though the “leaf” is only moving because of a light breeze.
If you blow on one it will also shake around in the hopes of matching any actual surrounding leaves
This is perhaps approaching graduate level information as far as digital costuming is concerned, but I think that the more fidelity professional game artists have access to, the more mindful the details ought to be. This is especially true in the case of low-tech/medieval/pre-industrial fantasy where everything in the world is handmade; these little details are really crucial to selling that look.