This spider's having a bad day. First a few humans stick it in a jar, and then, on the way into confinement, the spider breaks one of its eight legs. Luckily, the spider is resourceful enough to mend its own limb: In this video by Talking Lizard, a London-based creative media team, the spider spins a cast to help it heal.
To make the cast, the spider used its two pedipalps—a pair of appendages that look and function somewhat like hands at the front of the spider's body. And the silk comes from spinneret glands by its abdomen.
Spiders use their silk for more than spinning webs. Their varying glands produce different kinds of silk for different purposes. In fact, when spiders adapted to land from water they initially began producing silk to protect their bodies. Spiders can also make "silkhenge," vertical structures constructed from silk, "bridal veils" to protect smaller male spiders from their more aggressive female counterparts, and even slingshots.
With the ability to engineer all these creations, a simple leg cast seems to be no big deal for the jarred spider. The humans who put him in that jar, on the other hand, need to check themselves.