Legendary Creature - Human Cleric
With the help of Consuming Aberration and other strong Mill effects, it isnt hard to give yourself some solid options of spells to cast via Sarumans trigger
Arden Angel happens to work well as it has you pick a random number from one to four in order to trigger its effect, which is easily replicated with a four-sided die
It plays best in decks with lots of cheap utility creaturesIm imagining my opponent blows up something like Teval, the Balanced Scale and I turn it into Orcish Bowmasters, Ramunap Excavator, or Eternal Witness
Tangle and Spore Cloud Getting the ability to stall an opponent's attack is a great way to gain some tempo, but they'll likely swing back at you next turn
While there are some synergies, like copying Dark Depths or a huge creature to get in an attack, for the most part, Mirage Mirror is a fun value card but not especially powerful as a build-around-me