User blog comment:HTFan/What is the reason for Mr. Pickles' murders?/@comment-26242274-20150908131944/@comment-26245895-20150908144139

Someone who is a yandere can actually find a sense of serenity from killing others out of jealously and protection. They are so fixated on the protection/love of a person, that they literally will kill another person in order to satisfy both their need of being their friend and their protection. Quite simply, they are completely insane with no sense of morality.

Though you do make a good point. Since Mr. Pickles has very little screen time, it is more than likely he could be just a maniac who loves killing, but his actions could be believed to be out of being jealous or over-protective in the eyes of Lammy, doing it only for good intentions, so almost both when looked at a certain angle.