I don't know if we as a community knew this yet, but since serebii, and bulbapedo don't show it i thought I'd post it here.
I hit it with sucker punch khan in battle maison and its attack went up. So it's HA is justified now. I did this back in october so i assumed others would notice this by now but it doesn't seem like. --- 3DS FC: 3308 4781 6052 (Pokemon Y Ingame name is Isaac)