Urr, Crystal Path Eremite

Reversal (You may remove X counters from this
card, to prevent X damage that would be dealt to it.)
Whenever a opponent taps a land to add mana
to his mana pool, add a Mana Counter to
Urr, Crystal Path Eremite.
If an ability your opponent controls would
remove this card from the battlefield, you may
remove 5 Mana Counters from Urr to negate
that effect.