Bloodspawn
Bloodspawn first appeared in the single-player games Ultima VII: The Serpent Isle, as a requirement for the more powerful (or diabolical) spells. Prolonged exposure was said to drive men mad with power.
Bloodspawn was intended to be used as a Necromancy reagent in Ultima Online, under an early design. It is occasionally seen on some shards as a rare item, often worth a good deal of money.