Once this repugnant being subdues a human or humanoid victim, it forces its proboscis down the throat to inject an embryo into the host stomach. This parasite causes a gradual loss of intelligence, eventually degenerating into constant uncontrollable laughter as it approaches maturity and finally leaves through the digestive tract. Hosts survive, but may never recover their sanity.

   Gut-klaun have been known to befriend human children, finding them unsuitable as hosts, but can never comprehend their friend's attachment to older, host-worthy family.

   For reasons that need not be detailed, they are most commonly found in the sewers, where they can grow into myriad hulking forms.