At the beginning of each player's upkeep, Power Surge deals X damage to that player, where X is the number of untapped lands they controlled at the beginning of this turn.
Legalities
Not Legal
Standardbrawl
Brawl
Penny
Future
Modern
Pauper
Alchemy
Pioneer
Historic
Standard
Gladiator
Oldschool
Historicbrawl
Paupercommander
Explorer
Timeless
Legal
Duel
Legacy
Vintage
Commander
Premodern
Predh
Oathbreaker
Rulings
2004-10-04
This card knows how many were untapped even if it was not on the battlefield at the beginning of the turn.