Dark Fairy Maleficent is a Premium Box Tsum. She is a Limited Event Tsum and is not available from purchasing Premium Boxes outside of the event. She was introduced during the Japanese event 5th Anniversary Tsum Tsum History (January 2019) and the International event 5th Anniversary Tsum Tsum History (July 2019).
Dark Fairy Maleficent will clear one type of Tsum Tsum, and also clears Tsum Tsums surrounding any chains made during her skill. Her skill also clears surrounding Bubbles as well. Her base time is 4 seconds and her base number required is 28. Higher Skill levels reduce the number required.
Try to connect as many chains as possible within the time limit given by the skill, whether it's short or long, and if there are big/large tsum tsums, try to clear them by connecting them or connecting chains close to them. Connecting more tsum tsums gives you more points, so you need to be efficient when activating her skill. Although Dark Fairy Maleficent has the word "Dark" in her name, she does not count as an initial-D Tsum Tsum, most likely because her original Japanese name is "Evil Fairy Maleficent".