Order of operations....

[Metal Master]

Here's the situation from league one week:

Player A has a Feraligatr ex active with no bench and 30 damage from being knocked out. They have one prize left. Player B has a Quagsire Uf active with a Cursed Powder attached, two prizes left, and no bench. Gatr ex attacks, so what happens?

A) Player B wins by Gatr ex being knocked out from Cursed Powder and they take two prizes?
B) Player B wins by Player A having no bench.
C) Player A wins by Player B having no bench.
D) Player A wins by taking final prize.

Case in point, what order does it go in? Is quagsire knocked out then Cursed Powder activates, meaning Player A takes their prize first?

Hope this doesn't take too much out of ya. =P

 

[Big Daddy Snorlax]

This one isn't really so bad. You have to go through all the steps in the Attack, including effects of Trainers, before you look at who gets Knocked Out. From the Rulebook:

g) Do whatever the attack says. Do any damage first, then do any other effects, and finally, Knock Out any Pokémon that have damage greater than or equal to their Hit Points.

In your example, both Players win in two ways, Taking their last Prize and KOing their Opponent's last Pokemon.

E) Sudden Death

BDS