Parazoide's Null Energy

As an additional cost to cast this spell, sacrifice
a base land not tapped, cannot be conjured in
any other way.
When Parazoide's null energy enters the
battlefield add 3 {e} to this card.
{ut}{e}: add 2 mana of any color.
When Parazoide's null energy has no {e} left
Exiles it
Because of space the flavor text was not included