I thought this variant up myself, but after I thought of it, I also saw a reference to it as a modification of Mastermind in a journal paper somewhere. The idea is that after Player 1 submits their guess, Player 2 submits their guess and also has the option of choosing the number of black and white pegs seen by Player 1 for their guess (so the response could be a lie). Each player would only get one lie per game. Also, obviously if the code was guessed correctly, no lie could be used.
(ocultar) ¡Juega una partida en tiempo real contra un adversario conectado! Tan sólo debeís seleccionar por defecto la acción "Mover y permanecer aquí" y ¡recargar la página con la tecla F5! (TeamBundy) (mostrar todos los consejos)