The heroes storm the Temple of R’gu, the God From The Stars, to steal the Ruby of the Winged Master
Enter the Kingdom of Frog King in search of Treasure. What deal will you have to strike to get out alive?
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.