Prismatic Druid

Manaburst (You may sacrifice a land as you cast this spell. If you do, it pays for 3 mana of any color.)
Prismatic (Whenever you cast a multicolored spell, put a +1/+1 counter on this creature.)
Whenever a land enters the battlefield under your control, you may sacrifice it. If you do, add 3 mana in any combination of colors to your mana pool.