Stink Spirit

A Stink Spirit is, apparently, a spirit so disgusting that it appears as a smelly mass of sludge or ooze. One such Stink Spirit appeared in Spirited Away.

However, the Stink Spirit that appeared was actually just an river spirit that had been too polluted by garbage that needed to be removed.

Trivia

 * It appears that regular spirits become Stink Spirits when heavily contaminated by garbage and pollutants.