Scooby Doo and a Mummy Too is the twelfth (12th) episode from the original series. Spoiler Alert - details of Scooby Doo and a Mummy Too are below.
The Scooby gang is visiting the Department of Archeology at an unnamed University and is there to assist "the Professor" (last name unknown, but a friendly guy). They also meet Dr. Najib, who is also assisting the professor. The Department is in the process of restoring and displaying Egyptian artifacts, including, the mummy of Ankha.
Ankha is a 3,000 year old ruler of Egypt, who was extremely wealthy and ruthless. According to legend, Ankha's tomb is cursed and anyone who disturbs Ankha's resting place is going to be turned to stone by Ankha's mummy.
While helping the professor, Shaggy finds an ancient coin. Which the professor claims he has no idea of its significance or value. Shaggy accidentally sticks the coin in his pocket and the gang then heads out to pickup sandwiches leaving the professor alone.
While the gang is away, the Professor hears strange noises and discovers broken glass and what appears to be the mummy come to life. When the gang returns, they find the professor sitting at his desk, turned to stone. They also soon find Dr. Najib turned to stone, and the mummy missing.
After splitting up to look for clues, Scooby and Shaggy repeatedly run into the mummy. Whenever the mummy gets close, it just says "coin, coin." The gang keeps getting away, except for Scooby, who is caught by the mummy. Shaggy eventually finds Scooby turned to stone on the school's lawn.
Scooby eventually frees himself and finds Shaggy. They eventually find the Professor (tied up) and bags of quick drying cement to create the stone figures.
The cursed mummy of Ankha
The coin that Shaggy found is actually a key that opens a secret compartment in a little, ancient statute. That compartment contains a priceless diamond, which Najib was trying to pilfer.
Unlike the traditional Scooby Doo episode formula, there is no plan to capture the mummy, it just happens by accident.
In Where's My Mummy, Velma is technically one of the villains. She is not bad, in fact, she has nothing but good intentions - to scare away grave robbers like Evan Van Butch from Cleopatra's tomb.
Fred gets a point for unmasking in this episode.
In this 1969 episode, the Egyptian Mummy supposedly turns those who disturb its resting place to stone. Of course, the stone figures are created using quick drying cement.
In Scooby Doo Where's My Mummy (2005), Cleopatra's tomb (who just happens to be Egyptian) is cursed and those who disturb it are to be turned to stone. Velma, who is acting like Cleopatra, turns people into stone by using quick drying cement. Velma apparently remembered how Dr. Najib did it and used that same technique.