Nightmare Fuel / Akazukin Chacha

• The Frog, Bird, Yorges' Hypnotic Eyes, The Demon King and the creepy pig Buhi
• Yoshiko, the creepy school nurse, especially her entrance, who practices... extreme methods just to keep a sick Riiya from leaving the school clinic, including chasing him all over the school with a gurney, feeding him with an entire bottle of medicine, and attaching an IV line on him. And all because of a minor cold. Principal Urara and Rascal later reveal that the school does not have a nurse, and that Yoshiko is actually a ghost nurse who is said to make the sick even sicker.
• The demons who appear from the Gate to Hell in Episode 56. Unlike all the other villains on the show, these ones look far more realistic and disturbing.