Musings of the Chattering Skull

From the Introduction: Musings of the Chattering Skull is a standalone encounter designed for five 16th to 18th-level adventurers. A wizard’s skull has taken up residence in a frozen citadel, protected by icy servitors as it torments a nearby town. The players need to enter the stronghold and shatter the skull, fighting elemental servitors and the icy power of the wizard.