The skulls of Unknown Unknown, which have been plaguing the Grand Duchy of Tir for some time. They are easily identified by the crude sun symbol painted on the forehead of the skull and the faint black aura they give off under spells that detect magic or evil.
One of the earliest quests of the Band of Misfits was to collect these. The end result provided a house in T'Kashire, which still belongs to Band member Qau.