4 Avengers Meet TF2 Challange! This is a challenge/call-out to authors from all over Fanfiction to make an epic crossover that should have happened a long time ago, and that I'm surprised hasn't already been made. Avengers meet the characters of Team Fortress 2! Just imagine if the classes from TF2 did something such as fighting with the Avengers in New York? This crossover must happen!