An unseen character is, as you’ve probably guessed from the name, a characte from a film or TV show that, for whatever reason, never appears on screen. While usually played for laughs on most TV shows there’s at least one show where an unseen character remained, well, unseen, is because they literally couldn’t find an actress capable of playing them. Frasier.
The Predators, or Yautja for people familiar with extended universe material discussing their various planet-hopping exploits, are a race of fictional aliens with a hard on for hunting and making trophies of the most dangerous game in the universe. Something they are apparently so obsessed with even their religion revolves entirely around The Hunt.
In the MCU Thanos stands as the most intimidating and powerful villain the pantheon of heroes established in that universe has ever faced. While Thanos’ powers and abilities aren’t all that well defined in the films he appears in, at least according to the Russo brothers, he does have an indestructible asshole.
During his tenure as a politician and president, JFK met and shook hands with more people than Goro during the Mortal Kombat tournament and probably took about as much damage doing so. We say this because the man ended up with some seriously fucked up hands as a result of pressing the flesh.
The Matrix is a series celebrated for showcasing some of the most sick-ass martial arts moves ever seen in a blockbuster. A fact that makes it kind of unusual that none of the principle cast had a background in martial arts. Well that might have something to do with the producers insisting that they own the moves of any martial artist they hired.