Fear.

If there was anything that really made you nervous it was the Doctor, you didn't know why Harley had kept you with him, you had never been able to delve so deeply into his mind to understand why he cared so much about your presence, not that he ever let you do that. His constant monitoring of you was almost suffocating, leading you to wonder why you were there.

But Harley knew why, not only was he fascinated by your presence since you became his assistant, but he had actually started to nurture a feeling of affection towards you, so much so that even his mind refused to get into gear, but he enjoyed your company. Not even when he was human had he ever felt such a feeling, and the idea of hurting you was alien to his mind.

So he simply kidnapped you, making you live as best he could with him and his servants. That day was just like any other, next to his primal vessel, watching every movement that appeared inside the factory, but Harley seemed more restless than usual. His body covered only by the long black tunic, while the TV he had in place of a head, shone with unspoken feelings.