The anal stage of development can be used as a weapon by a child against his or her parents.

During the anal stage of development, children begin to assert their independence and control over their bodily functions, including bowel movements. This can lead to conflicts with parents who are trying to potty train them. In some cases, a child may refuse to comply with toilet training as a way of exerting their power over their parents. This can be seen as a weapon in the sense that the child is using their bodily functions as a means of resistance or rebellion. However, it's important to note that this is a normal developmental stage and not all children will use it in this way.