Ant Dueler (stylized as ANTDUELER) is the third game in the Undertale series, announced and released by Toby "Radiation" Fox in 2023.
In keeping with the subversive, meta-aware nature of Undertale, Toby Fox planned to trick its fans with the sequel. He saw a fan idea for Undertale 2 that was completely unrelated to the first game, and decided to do the opposite of that, thereby creating a double subversion with Deltarune. Of course, nobody got the joke.
With two installments setting Undertale up as an ongoing series, he then subverted that and made a "trequel" that was all but unrelated to either game.
Ant Dueler is an RPG–pet simulation hybrid that has players raising various types of ants for battle. Players can compete against in-game NPCs and other players through an online multiplayer service. Battle is solely turn-based, with no dodging system and no successful pacifistic actions.
The game hints at a multiple-endings system, which is reinforced by the divergent evolution of the player's ant, in both appearance and personality, depending on how they raise it. However, the story mode only has one ending. Toby Fox deliberately spread vague hoaxes that claimed otherwise.
- The game continues the pattern of all names of games in the series anagramming to each other.