Yes, even this show managed to churn some up.
- "The Planet of Oz":
- The evil algae in "Terror on the Titanic", as dumb as the episode was, especially the way that it possessed the scuba divers.
- "Attack Of The Vampire" features Dracula attempting to turning the world into vampires and manages to create a genuinely terrifying Vampire Superman.
- "The Fear" had Scarecrow using his gas to Mind Rape Batman into reliving his parents' deaths. It's both heartbreaking and terrifying.
- The twist in "The Krypton Syndrome" where after Superman prevents Krypton from being destroyed, he returns to Earth to find it a burning ruin. Robin doesn't recognize him and says that he's the only surviving member of the Super Friends (this was the only episode where Robin appeared without Batman). A world without Superman...
- Some viewers might see "The Ghost" as this due to the appearance of Gentleman Ghost (called "Gentleman Jim") and his plan for revenge involves turning world leaders, Superman, and Wonder Woman into ghastly looking ghosts.
- History of Doom in which Luthor and the League inadvertently killed the Earth when the former tries use some solar flares to fired at the latter and the League's shield which tried to block it, ended up merging with it and making a radioactive belt around the Earth. Granted the visiting head alien's reset button prevents this but still...just wow.