Some species of spider weave spider-shaped 'sculptures' into their webs using bits of leaves, small twigs, seeds and other detrius in order to confuse or distract preditors.
As far as I know these decoy-making spiders have only recently been discovered in a remote area of the Peruvian Amazon. But I discovered one by chance in 2016 while photographing in a graveyard in the south of France.
You can see from this photo how it would work. A passing bird would be attracted (as I was) to the spider 'sculpture', while the real spider (safely hidden in the shadows) goes virtually unnoticed.