Fauna
*Ostrakonskelos glossaklept*, the hard-legged tongue thief. A parasitic crab or louse that dwells in the mouth, causing intense and unremitting hunger.
A close relative of other Protean crabs, belonging to the infraorder Adulati. The segmented body has two cerci, nerve-rich organs which evolved from legs. The mouthparts are simple. The tongue thief relies on its host to chew food.
Tongue thieves mimic other prey species until swallowed, then use a numbing agent to paralyze the predator's jaw long enough to anchor to the tongue. This numbing agent blocks the nerves that signal satiety (fullness) to the brain.
Although they are parasites, tongue thieves' small eyes and grasping limbs help the host latch onto food.
Tongue thieves anchor eggs or spermatophores in the mouth of their host, where they wait for a thief of the opposite sex to arrive. Infant tongue thieves (called manca) pass through the host's digestive tract.
In the same way some human cultures use capsaicin in food, it is conceivable that other organisms might develop a taste for the tongue thief's numbing agent. Personal experimentation would be ill-advised. Assessment: expel parasite to reduce host hunger. Be alert for juveniles who may attempt to infest your mouth.