Yes, yes, we know. It's the scar on his eye.
But did he always have that scar? If he did, wouldn't he be called "Birthmark" instead of "Scar?" After all, a scar is a thing you get during your life, rather than something you name someone - or some lion - hoping they'll get a scar later in life so their name is appropriate.
Turns out, Scar wasn't actually always named Scar.
The character, originally voiced by Jeremy Irons, has appeared in Disney animated movies, TV shows and books multiple times - including in both sequels to "The Lion King," and the animated spin-off "Timon & Pumbaa."
But for information on Scar's past, you're going to have to look to a story in "The Lion King: Six New Adventures." The particular adventure, titled "A Tale Of Two Brothers," appropriately tells the back-story of young Mufasa and Scar, who at the time was named... Wait for it...
Why is that GIF of Scar so upset? That's because "taka" in Swahili translates to a few different things in English: want, which makes a lot of sense; as does desire. But most of the time, the word is used to mean either "dirt" or "garbage."
So Scar's parents named one of their kids Taka - meaning "garbage" - and the other kid Mufasa - meaning "king."
In case you're wondering how that piece of lion garbage got his name-sake scar, he tricked a buffalo named Boma into attacking Mufasa... But when Taka started started laughing at his own trick, Boma - and his herd of buffalo - attacked Taka instead.
After he was saved by his father Ahadi - which means "promise," by the way - and healed by Rafiki, the newly damaged lion said, "From now on, call me Scar. Father, I won't forget what happened today. I promise."
Yeah. So there you go. Scar got a literally garbage name, and now you'll never look at "The Lion King" the same way again!