Baal, Electro Archon

Commander ninjutsu {2}{u}{b} ({2}{u}{b}, Return
an unblocked attacker you control to hand: Put this
card onto the battlefield from your hand or the
command zone tapped and attacking.)
Whenever a Ninja deals combat damage to a play,
you get {e}{e} ( Two energy counters).
You may spend {e} as though it were mana of any
color as long as Baal, Electro Archon is on the battlefield.