The Elder Things cast Stoneskin on Agna and Ciprian to support their battle with the Mutate. They also made sure the party understood that letting the Mutate escape from the Laboratory would be devastating for Bohlvarai and the heroes both.
"What else do we need to know about the Laboratory?" Ciprian asked.
"The whole complex is protected by a Permanent Wall of Force. Additionally here are three small pentagonal stone chips cut from a pinkish translucent stone. We are not precisely sure what they’re used for, but we know they somehow are required for a locking mechanism to the vault that holds the Star Stela."