The Blightspire Monoliths

Inviolable (This card can't be discarded, exiled or sacrificed. Whenever it would be put into a graveyard,
put it into its owners hand instead.)
You don't lose unspent mana as steps or phases
end.
At the beginning of each end step, remove all
unspent mana from your mana pool. You lose 2
life for each unspent mana removed from your
mana pool this way.