The local children continually ridicule and jeer at Hassan's deformed father Ali by calling him "Babalu." The term "Babalu" is the same as calling someone the "Boogeyman." The maniacal Assef is the originator of Ali's rude nickname and he continually harasses Ali by calling him a "slant-eyed donkey" and asking him to smile in public. Ali is a sympathetic figure with congenital paralysis of the lower facial muscles, which leaves him with a permanent grimace. The local Pashtun children feel comfortable making fun of Ali and calling him Babalu because he is a Hazara. The Hazaras are a disenfranchised minority Shiite ethnic group living in Afghanistan, who have been oppressed and discriminated by the ruling Pashtuns for centuries. Since Ali is considered a second-class citizen, the callous children do not hesitate to make fun his deformity.

In The Kite Runner (Hosseini), we learn fairly early in the book of the divide between Pashtun Sunnis and Hazara Shi'a in Afghanistan: the former is the ruling class and the latter is a far lower class.  Ali and Hassan are Hazara Shi'a and the servants of Baba and Amir, who are Pashtun Sunnis.  The neighborhood children, led by Assef, who is the bully of the neighborhood, call Ali "Babalu" (38). This means "Boogeyman."  Just in case that is a word you are not familiar with, a boogeyman is an imaginary monster, the sort of monster you picture waiting for you under your bed or in your closet when you are a small child.  Assef taunts Ali relentlessly.  He says "Hey, Babalu, who did you eat today?" (39) and calls him a "flat-nosed Babalu" (38) and a "slant-eyed donkey" (38). Ali had had polio as a child, so he dragged his affected leg, and the references to his nose and eyes are no doubt because the Hazara are more Asiatic in appearance than the Pashtun, with different ethnic origins.