Spider's net trap
Net-casting spiders build special webs as Dr George McGavin explains. They first construct a framework from which to hang, before producing a different type of silk to make their net. This net is constructed when the front legs are stretched, meaning it is loose as they wait in ambush. When prey trigger their attack, the spiders stretch their legs out and downwards to throw the net over the animal, ensnaring them in a split-second.