Hunt the Wumpus is a two-player Magic minigame you just shuffle up and play.
The goal is to find and resolve the single copy of Shivan Wumpus so you can attack for lethal. Non-Wumpus creatures? Can't attack.

Each player starts with a token copy of Terramorphic Expanse in play, and a token basic land of each basic land type in the command zone.
Each turn, they may play one of these token lands from the command zone as though it were in their hand.
"Why a token?" you ask?
Why, because Tokens disappear forever on hitting the graveyard!
Sure, you can always sac a land to stop the Wumpus... but you're never going to see that land again, permanently cutting yourself off casting sections of the deck.
Terramorphic Expanse is your one 'freebie'. Cash it in to stop the Wumpus, or use it to shuffle the deck and mess up an opponents carefully planned draw.

Players draw from a shared library of 20 cards, and discard to a shared graveyard. If the deck gets exhausted, shuffle the discard pile back into the deck and continue as if nothing happened.

All cards in the deck are chosen to revolve around finding the Wumpus (wherever it may be), and preventing it from hitting the board. Once it's in play, it's in play. There is no card advantage to be found here, if you have to double-spell to set up the Wumpus the only way to get your hand size back up is skipping a turn. This is a game of attrition - hold out long enough to deploy the Wumpus.

In future, I'd love to add an "extra player" module to take it to 3 or even 4 players while keeping that eeny teeny predictable deck feeling. Before I do that I'd have to find the last four cards to finish it.