California Man-root (Marah fabacea)
Roots of this plant wait until our spring to put out these vines and tendrils. The roots can be up to several meters in length and weigh over 100 kg! (Wikipedia) The fast-growing vines are a "gravity parasite" (my word), using other plant's stems to reach up to the sun. Toyon Trail, near a wildflower hot spot. iPhone photo.