“ 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...”
“ A village where everyone goes blind sometime during puberty. What could be causing this? Perhaps something in their diet. Or some malignant gene. How would an entire village where only young childen can see function?”