This is a very powerful effect, however, you still need something to use that mana for at instant speed or an ability to sink that mana in
You could build a reserve of high power, low toughness sacrifice fodder in order to draw plenty of cards without draining your life away too fast, but then Greven, Predator Captain wouldnt get a proper power bonus
Map tokens come with an ability that lets you (at sorcery speed, so in your main phase with nothing else on the stack) pay 1 mana, tap the map token, and sacrifice it
The English version of the trading card game later released across North America in 1999
Which starter Pokmon should you choose
Memory Deluge One of the best card draw spells in blue, most games are over when a blue player is flashing back Memory Deluge