Dog Sees God is a play featuring thinly disguised versions of the Peanuts cast in high school. Snoopy was put down after getting rabies and killing Woodstock. Lucy is in an asylum for lighting the little redheaded girl's hair on fire and that's the tip of the iceberg.
Cirque du Soleil's Quidam was intentionally conceived by its creators as a show that would be darker, less whimsical, and more realistic than what the company had produced up to that point. They accomplished this by...telling a story about the commonality of loneliness and alienation through the eyes of a jaded preteen girl who learns to reconnect with others via a trip to a sometimes-melancholy Magical Land.
Richard Strauss's opera Elektra, based on the Sophocles play but turn the bloodlust and neurotism up to the eleven, and adds a sister-to-sister Les Yay moment.