This is an alternate ending of the movie The Lion King. Indeed, this was the ending in the earlier production of
the movie; however, producers alternated this ending as this first one was too horrific for a Disney Film and letting Scar be mauled by his hyena henchman was more interesting to Scar's death than simply having him burn to death as he did in this version. Ironically, the final scene was in fact based on an alternate ending of Beauty and the Beast where Gaston was killed by wolves, which was cut for the same reasons this ending was cut (i.e. it was too graphic for a Disney film).
In this early storyboard scene, while Pride Rock is burning and the hyenas battle the lions, Simba battles Scar atop Pride Rock. During their battle, Scar viciously claws Simba in the face, and the impact is so great, that Simba falls backwards. Then, while Simba is on his back, Scar walks towards Simba and says, "This is too easy; why, this is almost as easy as killing your father." Indicating that Scar killed Mufasa and also that he is about to kill Simba as well. Scar acts as if revealing the fact that he killed his brother and Simba's father Mufasa, was something he said by mistake, as indicated when he claimed "the cat's out of the bag". Simba reacts in shock. Before Scar's attempt kill Simba he says, "Goodnight sweet prince." A reference from the Shakespherean play 'Hamlet'. Scar leaps toward Simba preparing to murder him but just as Simba is about to die, he uses his hind legs to shove Scar off of him causing Scar to fall off the edge of Pride Rock.
Suddenly Simba hears a cry for help from below.
He sees Scar clinging onto the edge of Pride Rock who is trying to avoid falling into the burning flames far below him to his death. It is confirmed that it was indeed Scar who was calling for help as he does so once again. Although Simba is willing to let Scar fall and die, he decides to help him when Scar tells Simba that if he lets him fall he is then a murderer and that he will be no better than Scar, something Scar knows Simba is not. To make his security that much better, Scar even adds that Simba has won, and is now king (which is obviously a lie).
When Simba attempts to help Scar, Scar grabs Simba's mane and dashes him off the edge causing Simba to fall to his apparent death. But just before Simba is about to smash into the burning ground below he lands on a tree, breaking his fall and causing him to hit the ground with lesser impact. As Simba falls onto safe ground, the fire around him begins to spread, so Simba runs for his life, narrowly avoiding the fire. Although to Scar, Simba's survival was too far away to see, to him Simba simply fell until he was too small to see, causing Scar to believe that Simba fell to his death and that he had won. After Scar's evil laugh of victory, he gets consumed by the fire that engulfs Pride Rock, and burns to death.
It begins to rain and the rain puts the fire out. After Simba's near death, he goes to see if an unconscious lion is okay. When it is shown that the lion wakes up and smiles at Simba, it can be assumed that the lion is okay. (The lion's name was never revealed).
In this early scene, whether the hyenas ran away, were killed by the lions, or burned to death is unknown. Or whether Scar escaped the flames and lived or just died another way (for example, being mauled by the lions) is also unknown. As well as what happened to the lions, Timon, Zazu, Pumbaa and Rafliki, did they burn to death like Scar? Were they devoured by the hyenas? Did they simply run away from the battlefield and never return? All those questions are unanswered due to the fact that the video to that scene just ends when the unknown lion awakens.
It's been presumed that all copies of the original ending have been destroyed. However, storyboard art of the original ending exists and can be found in video form on Youtube.