Wyrm's Heart
First Appeared in Ultima VII: The Serpent Isle as a requirement for cold based spells. Said to be taken from Ice Wyrms.
Was to be used as a Necromancy reagent in Ultima Online, but the original design for Necromancy was scrapped. Wyrm's Hearts appeared in-game, but as very rare spawns. On most Shards a Wyrm's Heart is worth a good deal of money.