In the beginning, there was Verdant Force. The Tempest rare was created as a drawback-free alternative to Force of Nature, was one of the great Timmy-appeal beaters of Magic's earliest blocks, and, perhaps unintentionally, was one of the best multiplayer-focused cards of its day. Paying homage to it years later, R&D designed Celestial Force and Magmatic Force years later, and, now, Commander 2013 is due to contain the cycle's black member, Baleful Force. Of course, a horizontal cycle with four members is usually just incomplete - so it's almost guaranteed that there will be a blue Force in Commander 2013.
But what will it do? We know most of the card already: The Forces have proven a very tight cycle, as all of them are 7/7 rare Elementals for 5CCC with a triggered ability that happens at the beginning of each upkeep. All that remains are the name and the actual effect. So there are plenty of potential versions for the blue Force. Let's see if we can order them from most to least likely:
Tidal Force 5UUU
Creature - Elemental (Rare)
At the beginning of each upkeep...
- ...target player puts the top five cards of his or her library into his or her graveyard. (The Mind Seize blue-black-red deck has something of a mill subtheme, and if Baleful Force isn't in that one...)
- ...return target creature to its owner's hand. (There may already be a removal member of the cycle in Magmatic Force, but Unsummon is appreciably different from Lightning Bolt.)
- ...tap target permanent. It doesn't untap during its controller's next untap step. (This has a similar justification to the last effect, but might feel a bit too much like Frost Titan.)
- ...return target instant or sorcery card from your graveyard to your hand. (Interesting, but would lead to repetitive game states and probably be kind of oppressive.)
What do you think the blue Force will do? Let me know in the comments.