“ Feral teenagers:
Teenagers who run away from home to live in the wilderness may become feral. As they become more and more feral, they gain some supernatural powers (a la Peter Pan - ability to fly, things they imagine come true - possibly quite powerful), but at the expense of their humanity and ability to speak, comprehend complex subjects, etc. Maybe they have a leader: the most feral of them all.
A regression into a fantasy childlike state.”
“ Sneezing Sickness - A strange plant infection that causes its victim to spread the plants seeds by sneezing them about. Larger lumps of phlegm or saliva sprout is spat out in a sunny place, producing more of the plants. As the Magical version of seasonaly allergies the affliction is limited in term and non-life threatening.”