So here's your dilemma: the situation is dire, the enemy is powerful, and you need to do a lot of damage fast. But luckily, you've got one big strong guy on your side, and one smaller scrappy guy who's good at putting the hurt on people. So you have the big guy throw the little guy at the bad guy, and that's how you cook up a Fastball Special.
This maneuver gets its name from August 1976's Uncanny X-Men #100, in which the X-Men are facing robot duplicates of their mutant teammates. Wolverine says to Colossus: "Okay, then, just like we did it in the Danger Room--! The Fastball Special -- Execute -- NOW!" And Colossus throws Wolverine at the robotic version of the Angel.
This should not work, of course. The fact is that it's hard enough to throw something with great force and great accuracy, especially when the thing you're throwing is a short, hairy Canadian who is not at all aerodynamic.
However, this works wonderfully for a few very important reasons. First, comic books. Second, Colossus is immensely strong, and could probably throw anything at a robot and make it hurt. Third, Wolverine has an indestructible metal skeleton and a very fast healing factor, so he won't get killed when he hits the robot. Fourth, Wolverine has metal claws that can easily cut a robot to pieces.
And fifth: It looks really fucking cool.
So the Fastball Special worked so well and looked so cool, it got borrowed all over the place. Colossus and Wolverine still performed the maneuver the most, but sometimes Colossus was hurling another character, like Emma Frost, Kitty Pryde, or Nightcrawler, or Wolverine was getting hurled by another character, like Storm, She-Hulk, Beast (in the '90s "X-Men" cartoon), and the Thing (in a cartoon called "The Avengers: Earth's Mightiest Heroes").
One time, Colossus and Wolverine switched things up. In Uncanny X-Men #137, at the end of the Dark Phoenix Saga, Wolverine is able to use the lighter gravity of the moon to throw Colossus at Phoenix.
Outside of the X-Men, this move has also been used by the Thing and Mr. Fantastic (both sometimes taking the roles of thrower and throwee), Molly Hayes and Victor Mancha in "Runaways," Luke Cage and Iron Fist, Squirrel Girl and her squirrel Tippy-Toe, Superman and the Hulk (in the "Incredible Hulk vs. Superman" crossover), Cyborg and Beast Boy in the "Teen Titans" cartoon, Mr. Incredible and Elastigirl at the end of "The Incredibles," Negasonic Teenage Warhead and Deadpool in the first "Deadpool" movie, and Aragorn and Gimli in "The Lord of the Rings: The Two Towers."
So for the most part, it's an X-Men thing. But comics creators love to pay tribute to the iconic moments from comics' past -- and comics fans love to see those iconic moments re-worked with flair. And that's the best way to make something look really fucking cool.
Research:
TVTropes