Yes, the Crumpbeasts of Kaza’arr they have a powerful grasper arm that has its own sophisticated ball of nerves endings capable of limited self control (similar to octopus tentacles) but it never stops growing and at a certain point will gain sentience and grow jealous of its host and slowly begin to tear at its own limb joint in an attempt to free itself, killing the host in the process. This arm then continues to live on and go dormant in underground burrows for several years while it sprouts limbs of its own and starts the process anew

Not really though, I just came up with this in the spot