Ancient Mana Battery

Cannot be countered, indestructible.
{2}: Add {c} to your mana pool.
{3}: Gain {e} counter.
{u/r}{u/r}: Gain {e} counter.
"This.. ancient book claims it is possible to use
the molten core of our very planet as a mana battery.
But we will need a LOT of lightning to recharge it..."