[Harry Potter] A Little Turtle Soup for the Wizarding World

The Portkey deposited them in the wrong place. After a bout of dizziness, Harry found himself in an unfamiliar, pure-white space. Apart from a few chairs and his equally bewildered companions, there was nothing there.

Harry looked around. "Surely the Quidditch World Cup isn't being held here?"

Familiar and unfamiliar faces appeared one after another in the empty space. The uneasy atmosphere vanished when Dumbledore arrived.

After a mechanical voice read out the rules of the Sea Turtle Soup game, it presented the first puzzle:

[Four ears, three ears, one ear]

But--

Dumbledore received a special mission. A voice only he could hear whispered into his ear: "You are the impostor. Your questions will only receive the answer 'yes and no.' Ask at least one question each round, conceal your identity as the impostor, and lead them toward failure."

Theme: If you're playing Sea Turtle Soup, you have to ban Dumbledore!