A YouTube Video Mash-up is the combination of multiple sources of videos which usually have no relation with each other, other than a derivative work, often lampooning its component sources or another text. Many mash-up videos are humorous movie trailer parodies, a later genre of mash-ups gaining much popularity. To the extent that mash-ups are 'transformative' of original content, they may find protection from copyright claims under the "fair use" doctrine of U.S. copyright law.
The following (below) are just a few actual examples of YouTube Video Mash-ups that can be found on YouTube:
1. World's Finest Trailer - Batman vs Superman (Michael Keaton vs Christopher Reeve)
by silverlightsaber
2. Iron Man vs. Transformers Theatrical Trailer
by 2SunsNoWomen
3. Batman vs Iron Man trailer (Christian Bale vs Robert Downey Jr.)
by silverlightsaber
4. The Ultimate TV and movie car race. extended version
by gadget127
5. Psycho Street Hawk vs KITT
by gadget127
6. Batman vs Blade Trailer (Christian Bale vs Wesley Snipes)
by silverlightsaber
1. World's Finest Trailer - Batman vs Superman (Michael Keaton vs Christopher Reeve)
by silverlightsaber
2. Iron Man vs. Transformers Theatrical Trailer
by 2SunsNoWomen
3. Batman vs Iron Man trailer (Christian Bale vs Robert Downey Jr.)
by silverlightsaber
4. The Ultimate TV and movie car race. extended version
by gadget127
5. Psycho Street Hawk vs KITT
by gadget127
6. Batman vs Blade Trailer (Christian Bale vs Wesley Snipes)
by silverlightsaber
by The Centurion January 26, 2013