Scooby-doo Mystery Incorporated Season 1

The character designs are a love letter to the original 1969 series (Scooby has his original collar, Shaggy has the Adam's apple, Velma has the orange turtleneck), but the tone is radically different. This is Twin Peaks for children. There is a literal dark entity trapped beneath the city that communicates through dreams. There is a curse. And there is a body count.

Every classic trope (the chase scene, the unmasking, the catchphrase) is present, but usually followed by a tragic beat. When they unmask a villain in this show, the villain often cries, goes to jail for murder, or turns out to be a victim of the curse.

(a pun on "mystery"). He sends them clues regarding the "Curse of Crystal Cove" and the mysterious disappearance of the