Captain America chuckled. "I think that's a great idea, Tony. The world is full of heroes, and sometimes they come in unexpected packages."

The team waited anxiously as JARVIS worked his magic. Suddenly, a response came through.

"Alright, team," Captain America began, "our mission is to stop an alien invasion. Reports are coming in that an extraterrestrial force is heading towards Earth, and it's up to us to defend our planet."

The Hulk, aka Bruce Banner, grunted. "HULK SMASH PUNY ALIENS! BUT HULK ALSO SMART. HULK HAVE PLAN."

And so, the Avengers and the Xtm Avengers joined forces, combining their skills and expertise to save the world from the alien invasion. The battle was intense, with laser blasts and super-powered punches flying everywhere.

JARVIS explained, "It appears to be a game file, created by a group of gamers who call themselves the 'Xtm Avengers'. They're a highly skilled team of players who have been testing their skills on a custom-made game mod."

JARVIS nodded. "Already on it, Captain. I'm sending a message to their leader, 'Xtm Main'."

Spider-Man, the web-slinging teenager, piped up excitedly. "Whoa, guys! I've been tracking the alien's spaceship on my Spider-Tracker. It's huge! Like, a thousand times bigger than my web-shooters!"