Flameskulls

Flameskulls are the sort of monster most every adventurer has at least heard of, because there's always some guy in a tavern who claims he's fought one before. Formed out of the skulls of dead wizards, these literal floating flaming skulls are known for their mad laughter and ability to casually throw fireballs around. Your character knows what a flameskull is if they make a DC 10 Arcana check — DC 8 if they've spent a lot of time in big cities where there are more people talking shit in taverns.
The party encountered flameskulls at the Amber Temple.