Parasites that infest other parasites are called ‘hyperparasites’. Take crypt-keeper wasps, for example. They parasitise gall wasps, which parasitise plants. Gall wasps trick trees into building safe chambers for their larvae, forming strange growths called galls.
When the larvae mature, they usually burrow their way out, but crypt-keeper wasps intercept the process. They lay their eggs inside the galls, next to the gall wasp larvae. Under the influence of a crypt-keeper larva, a gall-wasp larva can only chew a tiny hole in its gall before it gets stuck. This gives the cryptkeeper larva time to eat the gall wasp larva, chewing through from tail to head and out into the open.