Enchantment, RR (2)
Rare
At the beginning of each player's upkeep, Power Surge deals X damage to that player, where X is the number of untapped lands he or she controlled at the beginning of this turn.
Illus. Douglas Schuler

10/4/2004: This card knows how many were untapped even if it was not on the battlefield at the beginning of the turn.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Commander