Headcanon time!
Alastor endured bullying during his childhood due to his mixed race and fatherless home life. It's noteworthy that some of the confrontations were not entirely unprovoked, as Alastor had a penchant for finding trouble himself. He often challenged peers who were physically larger and stronger than him. However, his responses to the bullying gradually took on a more menacing tone.
During one incident, Alastor lured one of his bullies deep into the bayou during a chase. The kid was ready to beat Alastor up, but Alastor had gotten away, taunting the other kid to try and catch him. Reaching a steep hill, with huge body of water at the end, Alastor halted. The kid had caught up to him, with a huge stick in his hand.
"Ready to get your ass beaten?" The kid taunted.
"Come and get me, if you dare!" Alastor retorted back.
The kid launched himself at Alastor, but Alastor swiftly dodged to the side, leaving his tormentor falling down the hill and into the murky waters.
Observing the scene, Alastor couldn't help but smirk. He noticed a crocodile approaching the struggling bully, who was now thrashing and screaming for help.
"ALASTOR! GET ME OUT OF HERE!" the bully shrieked in terror.
"I rather not." Alastor camly said back and turned away. "Best of luck chum!"
"Y-YOU CAN'T LEAVE ME HERE! No.. NO AAAAAAAAAAAAAAA!"
Back home Alastor had a nice meal waiting for him. He was smiling and humming as he ate his mother's' wonderful food.
"You seem to be in a good mood Alastor. Anything particular good happened today?" his mother inquired, delighted to see her son in high spirits.
"Oh, nothing of importance." Alastor sang back.