The board game Skull (in Serbian) is a game where the very essence is bluffing, a game that all takes place in the players' minds.
Each player plays a card face down. After that, the other players in the turn each add another card until someone is confident that they can turn over a certain number of cards and that all of those cards will have roses on them. Other players can then claim that they can turn over a greater number of cards that also have only roses. The player who claims to turn over the highest number of cards will have to turn over that many cards. If they are all roses, that player wins. If not, and a skull appears on one of the cards, they lose.
Skull is not a game of luck; it is a game of bluffing, trickery, and perception.