parent death, personal shit
"Upon evolution, Marowak has overcome the grief of its mother's passing. Now ferocious and violent, Marowak is an adept combatant that uses the bone it carries as a weapon and a boomerang." (Bulbapedia)
as a kid with a dead mom, I resonated with creepy kid cubone. cubone evolves at level 28. that's about when I evolved, too.