Rock Worm

The Worm is one of the three bosses to spawn in the Dark Caves.

Behavior
The Worm turns hostile after a player kills 3 crawlers or after a player attacks it directly.

Attacks

Strategy
The best bet is to wait until the Worm stops spitting poison, as it will stand still for a few seconds before burrowing again.

If you freeze the worms head using the frost nova or iceball spell he will stop spitting poison until the next time he resurfaces.

The worm takes increased damage to its head and reduced damage to its body.

It can only move so far into open space from any wall, floor, or other environments. Therefore, if the player is distanced far enough from an open space before the worm is close enough to begin firing its poison, the worm will recede and move back into the surface area to come from another angle.

If the player has such an environment, it can avoid the prompting the poison attacks altogether by getting far enough away that the worm is forced to recede, attacking its body as it leaves, and repeating until it dies.

Champion Variant
The champion variant has a gold coloration, and possesses a new attack.

If the player is close enough to it when it burrows out, it will lunge at the player, dealing around 25 damage on contact. If the player has less than 25 health, then the boss will instead grab the player and drag them back into the wall which will instantly kill them.