Aang, Energybender

+2: For this turn your lands have: "Tap: add 2 mana of any color".
-4: Tap up to 3 permanents your opponent controls. They don't untap during your opponent's next untap step.
-10: This turn, your spells/abilities cost {w}{u}{r}{g} less. Create a 10/10 white, blue, red and green token with Flying, Hexproof, Haste, Trample.