Parenting.

Nature is so amazing that parents do their job of protecting their next generation, but nature has always provided a tool that we humans named as 'Camouflage'.
Here this spider species lives on tree trunks, and if you can differentiate, its actually guarding its egg-sac, which is so well camouflaged that you need second look to see it. This spider built this almost super flat, making it merge with surrounding.