Khan: " Let me introduce you to Ceti Alpha V's only remaining indigenous life form; what do you think? They've killed twenty of my people, including my beloved wife. Oh, not all at once and not instantly, to be sure.
Their young enter through the ears and wrap themselves around the cerebral cortex.
This has the effect of rendering the victim extremely susceptible to suggestion. Later, as they grow, follows madness, paralysis -- and death. These are pets, of course -- not quite domesticated".