Scatha

 is a worm creature spawned within the Crystal Hollows when mining Hard Stone that can drop the Scatha Pet. They appear as a chain of heads with the same texture of the Scatha Pet. Every hit you deal will remove 1 from their health, similarly to Spooky Festival mobs. They start off with a chain of 10 segments, and decrease by one each hit until killed.

Spawning
They appear to spawn in small tunnels and will spawn within around 20 seconds after an area has been dug out. When they spawn, they make a unique sound, alerting players of their presence.