My Larvitar is poisoned with 10 HP left. My opponent has one prize remaining and no cards in the deck. Can I attack with "Mountain Eater" and win the game?
You can attack, but if you can't discard the card you don't get to remove two damage counters. Larvitar will be KO'd between turns and your opponent will take the last prize.
Source:
Unleashed FAQ (2010-05-13), PUI Rules Team (2010-05-13)
The damage from Tyranitar's "Power Claw" attack isn't affected by Poke-POWERS, Poke-BODIES, or any other effects on the Defending Pokemon. Would you apply weakness and resistance to its damage?
Yes, weakness or resistance to Tyrantitar's type would be applied where appropriate. These are game rules and not considered effects on the Defending Pokemon.
Source:
Unleashed FAQ (2010-05-13), PUI Rules Team (2010-05-13)
If Ariados' "Leech Life" attack does 30 damage but the opponent's Active Pokemon has only 10 HP remaining, how many damage counters will be removed from Ariados?
Leech Life does 30 damage, which is not affected by the fact that the KO only required 10 damage. Therefore, Ariados will remove 3 damage counters, or all if there are less than 3.
Source:
HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)
If the Defending Pokemon doesn't have any Energy cards attached to it, does Typhlosion's "Flare Destroy" attack still require Typhlosion to discard an Energy from itself?
Yes, if the attacking Pokemon has any Energy cards attached, it must discard one of them.
Source:
HeartGold & SoulSilver FAQ (2010-02-11), PUI Rules Team (2010-02-11)