This is basically the technique whereby the prey animal becomes indistinguishable from its background, to avoid predator detection. This can be via background matching, whereby the animal visually resembles objects in its environment. For example; Extatosoma tiaratum, Extatosoma tiaratum green, Phyllium celebicum all resemble dead leaves.

This can also be through disruptive colouration, whereby the body of the prey animal either has features that detract from the shape of the animal itself. For example; Oreophoetes peruana, Pseudophasma acanthonata.

Countershading is another way that a vulnerable animal can blend in with its background. Basically, any solid object of uniform colour will appear brighter on the side from which it is lit (e.g. by the sun). Animals that take advantage of countershading usually have brighter colours on the underneath of its body, and darker colours above. When illuminated from above the greater ambient light intensity at the top is reflected less by the dark dorsum and the lower light intensity below is reflected more by the pale ventrum, the result being a loss of the 3D appearance. As far as I'm aware, this technique is not really used by mantids or phasmids.