Movement in an entangled cluster of worms: How active polymer chains can self-organize into solid-like clusters

Earthworms often form a cluster, from which they can barely free themselves. A similarly active, writhing structure forms when the tentacles of lion's mane jellyfish become entangled. Robotic grippers utilize this principle by using multiple synthetic flexible arms to grip and move objects. And such interlinked self-propelled filaments can also be found at the smaller micrometer scale, for example in a biological cell.