Mirrodin Besieged has a five card cycle of very powerful spells with Zenith in the name. All of them refer to one of the suns on Mirrodin; for example, Black Sun’s Zenith. One aspect of these cards that makes them so good is the fact that they are reusable. When a Zenith resolves, the card itself is shuffled into its owner’s library, where it can potentially be drawn and played again. However, the Zenith’s are only shuffled into their owner’s library if they do indeed resolve. If the Zenith spell is countered, either by a spell or ability or countered on resolution, then the Zenith spell will go to the graveyard. All of the Zenith spells can be countered by spells and abilities, but because both Blue Sun’s Zenith and Red Sun’s Zenith target they can become coutnered on reoslution if their target is not legal when they attempt to resolve.