https://www.cnet.com/news/scientists-discover-new-parasitic-wasp-that-creates-spider-zombies/

Once the wasp's deposited egg hatches, a larva emerges, attaching itself to the spider and feeding on it, sucking on the blood-like haemolymph to survive. At this point, the spider's behaviour changes and it becomes enslaved by the larva, moving away from its communal nest to create a cocoon-shaped web of its own.

The larva feeds on the spider until it dies, in the relative safety of the cocoon-shaped web its host just built before spinning its own cocoon and, eventually, emerging as a beautiful, regal wasp.