Ionization Cannon

Reach, Trample, Cascade 2, Doublecast 1
When Ionization cannon enters the battlefield,
choose a mana type. Whenever a spell of the
chosen color is cast, Ionization cannon deals
damage to any target equal to a third its converted
mana cost (Rounded down).
Ionization cannon's power is equal to your
devotion to the mana type you chose.