Specter
Specters are aggressive, malevolent ghosts with tremendous abilities to disrupt the psyches of living creatures. Whilst the game's original specter, Hypnotic Specter, appeared as a wraith-like, free-floating knight, subsequent Specters have normally been depicted as commanding massive, winged mounts similar to Tolkien's fell beasts (Later printings of Hypnotic Specter featured updated art that also depicted this mount). Specters tend to be free-willed beings serving no master.
In the game, Specters normally have abilities that force the opponent to discard cards from hand once damaged, simulating the Specter's psychic interference. This disruption, combined with the Specter's ability to fly and therefore evade most blocking creatures, means that they have often seen heavy tournament play. Due to the prominence given to the mount in most Specter card illustrations, many players wrongly believe that the mount itself is the specter.
(Abyssal Specter, Shimian Specter)
Read more about this topic: List Of Species In Magic: The Gathering