The Lion King

In the Pride Lands of Africa, a lion rules over the animal kingdom as king. The birth of King Mufasa and Queen Sarabi's son Simba creates envy and resentment in Mufasa's younger brother, Scar, who knows his nephew now replaces him as heir to the throne. After Simba has grown into a young cub, Mufasa gives him a tour of the Pride Lands, teaching him the responsibilities of being a king and the Circle of Life. Later that day, Scar tricks Simba and his best friend Nala into exploring a forbidden elephant graveyard, despite the protests of Mufasa's hornbill majordomo Zazu. At the graveyard, three spotted hyenas named Shenzi, Banzai and Ed attack the cubs before Mufasa, alerted by Zazu, rescues them and forgives Simba for his actions. That night, the hyenas, who are allied with Scar, plot with him to kill Mufasa and Simba.
The next day Scar lures Simba to a gorge and tells him to wait there while he gets Mufasa. On Scar's orders, the hyenas stampede a large herd of wildebeest into the gorge. Mufasa rescues Simba, but as Mufasa tries to climb up the gorge's walls, Scar throws him back into the stampede, where he is trampled to death. After Simba finds Mufasa's body, Scar convinces him he was responsible for his father's death and advises Simba to flee the kingdom. As Simba leaves, Scar orders Shenzi, Banzai and Ed to kill the cub, but Simba escapes. That night, Scar announces to the pride that both Mufasa and Simba were killed in the stampede and steps forward as the new king, allowing a pack of hyenas to live in the Pride Lands.
After running far away, Simba collapses from exhaustion in a desert. Timon and Pumbaa, a meerkat and a warthog, find him and nurse him back to health. Simba subsequently grows up with them in the jungle, living a carefree life with his friends under the motto "hakuna matata" ("no worries" in Swahili). When he is a young adult, Simba rescues Timon and Pumbaa from a hungry lioness, who turns out to be Nala. She and Simba reunite and fall in love. Nala urges Simba to return home, telling him the Pride Lands have become a wasteland with not enough food and water. Feeling guilty over his father's death, Simba refuses and storms off, leaving Nala disappointed and angry. As Simba exits the jungle, he encounters Mufasa's mandrill friend and advisor, Rafiki. Rafiki tells Simba that Mufasa is "alive" and takes him to a pond. There Simba is visited by the ghost of Mufasa in the sky, who tells him he must take his rightful place as the king of the Pride Lands. Simba realizes he can no longer run from his past and goes home. Nala, Timon, and Pumbaa join him, and agree to help him fight.
At the Pride Lands, Simba sees Scar hit Sarabi and confronts him, but Scar taunts Simba over his "part" in Mufasa's death. However, when Scar pushes Simba to the edge of Pride Rock, he reveals that he killed Mufasa. Enraged, Simba roars back up and forces Scar to reveal the truth to the pride. Timon, Pumbaa, Rafiki, Zazu, and the lionesses fend off the hyenas while Scar, attempting to escape, is cornered by Simba at the top of Pride Rock. Scar begs Simba for mercy, insisting that he is family and placing the blame on the hyenas. Simba no longer believes Scar, but spares his life on the grounds of forever leaving the Pride Lands. Scar appears to comply, but then attacks his nephew. After a fierce fight, Simba throws his uncle off Pride Rock. Scar survives the fall, but is attacked and eaten alive by the hyenas, who overheard his attempt to betray them.
With Scar and the hyenas gone, Simba ascends to the top of Pride Rock and takes over the kingdom as the rain falls again. Sometime later, with Pride Rock restored to its former glory, Simba looks down happily at his kingdom with Nala, Timon, and Pumbaa by his side; Rafiki presents Simba and Nala's newborn cub to the inhabitants of the Pride Lands, and the Circle of Life continues.

Question: What does scar beg simba for?
Answer: mercy