What did Romeo do when Tybalt returned to the scene?

Answer 1

The answer to your question depends greatly on which scene you're talking about. For now I'll assume you mean the scene in which Romeo kills Tybalt. This is Act III Scene I.

This is the first scene after Romeo weds Juliet. Tybalt is actually Juliet's cousin, so when Romeo refuses to fight Tybalt ("Tybalt, the reason that I have to love thee/ Doth much excuse the appertaining rage/ To such a greeting. Villian I am none./ Therefore farewell. I see thou knowest me not." --Romeo, Act III, scene i.), Romeo's friend Mercutio fights Tybalt instead, and in the end Mercutio dies.

Romeo is furious. He challenges Tybalt and kills him, which leads to Romeo's banishment.

Of interesting note is that this scene is actually the climax of the play.

In performance, the scene opens with Benvolio and Mercutio onstage. Tybalt joins them, looking for Romeo. Romeo then arrives, and the fight between Tybalt and Mercutio takes place onstage. When Mercutio is wounded, Tybalt flees, and Benvolio helps a cursing Mercutio offstage. He returns shortly with the news that Mercutio is dead. It is at this point that Tybalt "returns to the scene" as the question asks. Romeo then explodes at him, telling him that Mercutio's spirit is just overhead and "either you or I or both must go with him." Then follows the fight between Romeo and Tybalt.