Public lobbies in video games typically consist of people who don't know each other, and in social deduction titles like Among Us, this creates the perfect playing field. For Crewmates, the game revolves around being able to spot tells and lies so as to catch Impostors, and for Impostors, the game revolves around being able to get away with lies to murder Crewmates. This concept works best in lobbies filled with people who don't play together too often and so don't have much prior info to work with.
An Among Us fan going by the tag PhantomHylian on Reddit took advantage of this fact to secure a victory as Impostor. When the Redditor accidentally killed someone in front of a Crewmate, they turned the situation in their favor by pretending their accuser, AlexAce, was their Impostor partner, one who was new to the game and didn't know to avoid reporting their partner's kills. The act made the accuser so suspicious that Crewmates threw them out after Phantom, giving the latter's team victory.
The ploy worked because no one in the lobby knew each other, so AlexAce had no real way to defend themselves against Phantom's act. If everyone had at least some prior experience with one another, Alex's fellow Crewmates might have seen through the rather humorous lie. They could have used knowledge of his playstyle or even his personality to determine whether he would actually mess up like that, even if he really were a new player when the accusation happened.
Beyond all of this, though, Phantom's lie is hilariously reminiscent of old Among Us memes, particularly ones revolving around new players asking the rest of the lobbies why their names aren't red like theirs and their partners. Like Phantom's ploy, these play on the idea that new players don't exactly know what they're doing, and as a result, end up getting themselves and their Impostor duo killed. It's funny to see the tactic instead used by an Impostor to successfully get a crewmate killed.
Developer InnerSloth plans on making Among Us lobbies 15 players soon, so the potential for the game's shenanigans should increase by quite a bit. The idea of 15 people typing at once already sounds hectic; following the conversation should prove a challenge in and of itself. Who knows, maybe some new big-brain plays will arise from the expanded numbers. After all, it's rare for lobbies to fairly utilize three Impostors.
Among Us is on Mobile, PC, and Switch. PS4, PS5, Xbox One, and Xbox Series X/S versions in development.