The Giant Malaysian Leaf Insect (Phyllium giganteum) is limited to the Taman Negara rainforest in Western Malaysia, one of the oldest rainforests in the world being roughly 130 million years old.
As the name already suggests, it perfectly impersonates being a leaf among many in the trees they inhabit, mostly sitting still and being unreactive. Females are the bigger sized with 12 centimeters. Contrary to the females, the males (9 centimeters in length) have long wings and can fly.
While moulting they're very vulnerable and can die easily if either temperature or humidity of the environment aren't ideal, of if they're touched while their bodies are still soft, which makes raising them in captivity very difficult.
Fun fact: females don't require males in order to reproduce offspring. However, if male offspring is desired, then a female must breed with a male, otherwise all offspring will be female. In part due to this capability of the female leaf insect, the first male Giant Malaysian Leaf Insect wasn't discovered until 1994. Therefore, comparatively little is known about the males of this insect species.