MurderCraft

Each session runs four rounds, and each round lasts up to 15 minutes. At the start of a round every participant is secretly given one of three roles: murderer, detective or innocent. Murderers are hidden and stalk the crowd, while the detective is the only player with a pistol that carries a single bullet. The round ends early if the innocents and detective eliminate both murderers, or the murderers win by killing a non-murderer before the timer runs out. Whichever side collects more round victories claims the session, with a 15-second breather between rounds before roles are dealt out again.

Ahead of every round, players are moved to random valid land spots inside a radius the server can set, which defaults to 200 blocks. Spawns are kept apart by a minimum distance that scales with the number of players, and players receive a short period of damage immunity as the round starts. Participants are switched to survival mode for fair play, and the world border is set automatically around the world spawn at the start of a session. A server running it needs every connecting player to have it too.