Ice walls
Heading down one of the tunnels together, the vibrations from the strange screams were getting louder and louder. They were starting to worry that the cave would collapse just from the loud screams alone, but the material that the cave was made from, although it looked fragile like glass, was far more robust than it appeared.
Some of the men tried to chip away at the tunnel walls using the normal tools they had brought with them to send back samples to the lab. However, they were unable to and only high level beast equipment could break such a thing. Since the discovery of new planets, nearly everything new they found, minerals and materials, were to be sent back for research purposes.
Proceeding with caution, the loud cries from the creature seemed to have stopped.
"Why do you think it was making so much noise?" One of them asked. "I've never heard a beast make a sound like that."