While hunting for the Popularity Potion and digging things out of the chest, Sardo mutters "Super Specs", a reference to "The Tale of the Super Specs".
The only story where there was supernatural but no evil (it was about a door that showed the future and was a portal through space, though the supernatural there did not cause but only revealed havoc which was in itself natural).
One of the few episodes where Kiki doesn't wear a bandana.