When playing as a Loremaster, specifically a Beckoner/Illusionist, it seems the Illusionist passive is passed on to the wurms (after using Gernisc Slew the Beast, But Soon Faced Its Kin,) causing a huge number of non-aggro/non-despawning wurms to appear on the screen, eventually to the point of crashing the game.
The wurms don't attack anything, but they will break stealth if you cross their path.