I'm with Luftstalag here. Nainggolan deserves severe punishment for sure....
Only I'm not as kindhearted and forgiving as Lufts. For me to be satisfied with his punishment Nainggolan needs to be tortured most mercilessly. His funky haircut needs to be shaved off, and some chemical needs to be applied to his head so no hair can grow henceforth. Further, some manner of shrinking potion needs to be applied to him to reduce his size a considerable amount, forever cursed to roam the earth as a dwarf. Failing that, at least hire a Witch Doctor to shrink his head, if we cannot shrink his body, his head would have to suffice. Finally, as direct punishment to his misbehaving and murderous legs, Harry Potter would need to be summoned so he can apply a most devilish jinx on his legs so that they face backwards. This way, he won't ever be able to tackle anyone else since his body would be facing the would be victim, but his legs would be facing the opposite direction.
He should forever be known as the Bald and Shrunken Headed Dwarf that walks backwards.