The Venus Flytrap

Or also known as Dionaea muscipula, is a carnivorous plant that catches and digests animal prey, mostly insects. Its trapping  is formed by the terminal portion of each of the plant's leaves and is triggered by tiny hairs on their inner surfaces. When an insect or spider crawling along the leaves contacts a hair, the trap closes if a different hair is contacted within twenty seconds of the first strike. The requirement of redundant triggering in this mechanism serves as a safeguard against a waste of energy in trapping objects with no nutritional value.