A Worm or Scatha has a 1/600 (0.167%) chance of spawning when breaking Hard Stone in a tunnel of any width and height[Confirm] within the ⏣ Crystal Hollows. There is a 30 second cooldown every time a Worm is spawned. A Worm has an 80% chance of being spawned while a Scatha has a 20% chance of being spawned instead. The Heart of the Mountain Mole perk will not prevent Worms from spawning.
After digging out a suitable tunnel, breaking the blocks at the player's eye level on the side can still trigger Worm spawns. Breaking the blocks below foot level will also spawn worms.
While spawning, they make a unique squelching sound 3 times, alerting players of their presence, and the message "You hear the sound of something approaching..." will appear in chat.
A Worm appears as a chain of heads with the same texture of the Scatha Pet, and will slowly slither through the tunnel it spawned in. It has 5❤ Health and deals 400❁ Damage. They start off with a chain of 5 segments, which decrease by one each time they are hit until killed. Each hit deals 1❤ of damage to the Worm.
Trivia[]
Worms can be spawned while mining with an Armadillo Pet.