Dwarven beards are rich habitats for the enterprising critter.
Patron deity of the Cult of Done, Othamm is always working to counter Mathom's influence.
When Vegma, Judge of the Dead, was called away to witness Mathom's trial, he left Slys in charge of the recently deceased. Intended as a simple placeholder, she has come to be something more.
Animals have parasites and diseases, so do plants, there are even bacteria that cann dissolve oil spills or plastic or what have you - why couldn't there be a disease living off magic - a magic item could be infected, losing power and speading the plague to other equipment it contacts, while a magic user would slowly lose his powers and contaminate all he works with or casts a spell at...