Brain crawlers were a species of parasitic worm found on Cheelit. They could infest the brains of members of the happabore species. The instruction manual for Happy-Bore Medicated Dewormer—a product containing Trestibinexocycline 5-Gamma, thlank oil, greel-root acid and forage products, that was produced by Galacti-Stok—recommended that the dewormer not be used to treat brain crawler infestations.