In our games of Cosmic Encounter, it's not uncommon for more players to win than lose. In fact, it's less a game of winning than it is a game of not losing. But here's my idea for a variant with only a single winner, which I call Highlander (because there can be only one!)
1. When a player gets their fifth foreign colony, they become a Highlander for the remainder of the game.
2. If at any point a player is the only Highlander, they win.
3. If, at the start of a Highlander's turn, that Highlander has more trophies (see below) than any other, the Highlander wins.
4. Highlanders follow the normal rules for using the destiny deck and choosing which planet to attack, with the following exception: a highlander may target foreign colonies belonging to other Highlanders, instead of only being allowed to target the player who owns the system. In such a case, the targeted Highlander is the defender, not the owner of the planet.
5. Whenever a Highlander destroys another Highlander's colony, foreign or otherwise, the attacker keeps one of the defender's ships as a trophy. The rest of the defender's ships go to the warp, as normal. The trophy is kept on the attacker's alien power card and may not be regained or deployed for the remainder of the game.
Expansion by Ian Toltz