In 2007, when we were camping at Arabuko Sokoke National Park in Kenya, we almost missed this mantis hanging out on a tree trunk. The tree was in the center of a canopy structure and we must have passed it a dozen times a day. We think this is a species of twig or lichen mantis, Sibylla pretiosa. They range all over southern Africa.
The camouflage on this mantis is INCREDIBLE. Its body and legs look like spindly little twigs covered in lichen and the wings look exactly like leaves. Camouflage is a type of crypsis. This is where an animal avoids detection, either to avoid being seen by a predator or to successfully ambush prey. (Or avoid having its picture taken by curious entomologists.)