The first formal contact between the Federation and a Gamma Quadrant people, the game-loving Wadi, which went awry when Quark cheated them and Sisko's officers were drawn into their game Chula.
In the Deep Space Nine episode Move Along Home, Commander Sisko prepares a full diplomatic reception for the Wadi, the first delegation to come through the wormhole. Their leader, Falow, has no interest in ceremony and heads straight for the gaming tables at Quark's.
When the Wadi catch Quark rigging the dabo wheel against them, Falow makes him play Chula, a board game with living pieces. Sisko, Kira, Dax and Bashir vanish from their quarters and find themselves inside a maze of puzzles and hazards, chanting rhymes and dodging poison gas while Quark makes their moves.
Odo and Quark believe the players' lives are at stake, and Quark grovels when told to sacrifice one of them. The officers reappear unharmed; it was only a game. The Wadi leave, and the contact comes to nothing much.