The Cursed Treasure is supposed to be a conquistador treasure hidden long ago at the site of what is now Crystal Cove. The Pieces of the Planispheric Disk are a clue to find it, because the old Spanish explorers used such things as navigation aids and also to mark the location of their hidden treasures. The Planispheric Disk is the key to finding it.
There is supposed to be a curse associated with this particular treasure, one that has been eating away at Crystal Cove and which could destroy it. Professor Pericles claims that it is a treasure beyond calculations and that many have died trying to find it.
Inside the Crystal Sarcophagus is an evil Anunnaki that had been behind several of the evil events within Crystal Cove; whenever it spoke, the Black Pearls inside of the Sarcophagus start to rattle. After Scooby awakened from his nightmare, he warned his friends that the treasure was evil and had to be destroyed.