Turning Undead
The ability to “Turn Undead” is a legendary ability of Clerics. At higher levels, Clerics have been known to turn entire armies of Skeletons to dust with a wave of their hand. Their ability to Turn Undead, combined with their healing spells, means most adventuring parties are wise to have at least one Cleric in their ranks.
To Turn Undead, a Cleric uses their action to “boldly present their holy symbol”. All Undead within 30 feet must make a WISDOM Saving Throw or run in fear. Affected Undead cannot attack the Cleric or take any actions, aside from moving away from the Cleric as fast as they can. This effect stops immediately if the Undead takes any damage. The Difficulty Number for the Undead’s Saving Throw is listed on the Cleric’s character sheet. A Cleric’s Spell Difficulty is calculated as:
8 + your Wisdom Bonus + your Proficiency Bonus.
So Drizzy, from Adventure 050, has a Spell Difficulty Number of 8 + 3 + 2 = 13.
All the “Glitter” creatures the players encounter in Adventure 051 are considered “Undead”.