Other known variants
+30
-20Fainting Spell
Once during your opponent's turn, if Gengar would be Knocked Out by damage from an attack, you may flip a coin. If heads, the Defending Pokémon is Knocked Out.
Shadow RoomPut 3 damage counters on 1 of your opponent's Pokémon. If that Pokémon has any Poké-Powers, put 6 damage counters on that Pokémon instead.
PoltergeistLook at your opponent's hand. This attack does 30 damage times the number of Trainer, Supporter, and Stadium cards in your opponent's hand.
Gengar is receiving errata for its Poke-POWER, "Fainting Spell". Fainting Spell affects your opponent's Attacking Pokemon, not your Defending Pokemon. The correct card text should read, "Once during your opponent's turn, if Gengar would be Knocked Out by damage from an attack, you may flip a coin. If heads, the Attacking Pokémon is Knocked Out."
If Gengar uses "Shadow Room" against a Lv.X Pokemon that has no Poke-POWER, but the card underneath the Lv.X *does* have a Poke-POWER, does "Shadow Room" place three or six damage counters?
The Lv.X Pokemon has the Poke-POWERs and Poke-BODYs from the card underneath it, so Shadow Room would place six damage counters in this situation.
Does Marowak's "Bodyguard" Ability prevent me from revealing my hand from an opponent's Trevenant's "Poltergeist" attack?
Yes, it does.