6. "Be Prepared" - The Lion King
One of the most beloved Disney films of all time, The Lion King (1994) is basically Hamlet with lions and singing. Scar is deliciously evil as he murders his older brother and orders his nephew (only a cub) to be torn apart by hyenas. Like Jafar, Scar understands that if you go bad, you have to go all the way. Of course, in a way, Scar was unfairly judged for evilness by the other lions before Simba's return.
The drought wasn't actually his fault. Scar may be a murderous usurper, but he can't control the weather. Keeping Zazu in a cage made of rib bones wasn't his most magnanimous act, but he wasn't wrong when he said that it was the lionesses' job to do the hunting. Really, if it hadn't been for the regicide, fratricide, and ordered murder of his nephew, Scar could only be accused of doing the best that he could under bad circumstances. He just wanted to be king. Part of why Scar is remembered as such a great villain is because he was the smartest character of the entire film. He managed to recruit fearsome allies in the hyenas and planned his coup so minutely that it actually would have worked perfectly if his main trio of hyena advisors hadn't allowed Simba to escape alive. Scar was smaller and weaker than Mufasa but still managed to kill him. Besides, if the tables had been turned, Scar definitely would have realized much earlier that Mufasa was plotting against him rather than only when hanging off of a gorge above a wildebeest stampede.
"Be Prepared" is an amazing song, perfectly encapsulating everything that is Scar. He's classy and smart and does the plotting while his foot soldiers do the trotting. Surprisingly charismatic for a villainous lion, the entire scene plays as very Hitler-esque, with Scar promising food and prosperity to a legion of goose-stepping hyenas. (Seriously: watch it again. The hyenas goose-step.)
All in all, we can see with "Be Prepared" why Scar was probably going to succeed.
Most villainous lines: "The future is littered with prizes and, though I'm the main addressee, the point that I must emphasize is, you won't get a sniff without me!"