Theros features monsters of myth, such as Hydras, Minotaurs, Centaurs, Gorgons, and more. It also has gods and heroes that are reminiscent of Greek myth. These all work toward the new mechanics found in this set.
With all of these terrible beasts in Theros, there is a new mechanic called Monstrosity, where a creature can be pumped up with a bonus at an extra mana cost. In this exclusive look at the Arbor Colossus, it can be seen that when it becomes Monstrous, this Colossus can instantly destroy a flying creature.
Read the full article at MTV Geek.