Hello, I'd like to help you with your question.
When someone purposely does something to get a reaction out of another person, they are usually considered manipulative. Although a more definitive answer depends on details like the circumstances, what the person is saying or doing to get the reaction and the person's history of behavior, most of the time the person is using manipulative behavior.
One possible motive for saying or doing something to get a reaction is when a person is a relationship wants to know what their partner is feeling, but instead of just asking, they say or do something to get a reaction. For example, the person tells their partner that someone else was interested in them. The partner reacts and the person knows they care.
Another possible motive could be to hurt the other person. A person may trick someone by saying something untrue to see the person get upset and react, only to find out that they were being mislead.
Usually, a person who treats others in this manner is thought to have a personality disorder. The need to mislead in order to hurt or change someone's behavior comes from self centered motives. The person may derive pleasure from it in some form or another. This behavior is usually learned as a child where the person did not have their needs met, possibly through abuse or witnessing their caregiver hurting someone in a similar manner.
I hope this helped you,