"In the Maze there were serpents that could turn you into stone with a glance."

Saint Michael killing a Basilisk
Public DomainSaint Michael killing a Basilisk - Credit: wikimedia commons

Rick is probably referring to basilisks or something similar, which are legendary creatures that can kill a person with a glance. The basilisk is said to be the King of Serpents, and is often shown in medieval art as a reptile with the head of a cockerel or dragon, with a crest on its head. The basilisk appeared in Harry Potter and the Chamber of Secrets as an enormous serpent that could kill with its stare, or petrify a person if seen indirectly, such as in a reflection. Turning a person to stone with a glance is a power that belongs to Medusa, a monster of Greek mythology who appeared as a woman with snakes for hair. The monsters described in the Maze are probably some kind of combination of the two.

Harry Potter and the Chamber of Secrets on Book Drum.