Pumpkin Mickey is a limited time Tsum that was made available in October 2015 in the International version of the game. Since his skill is maxed at level 3 he isn't the most powerful Tsum; however, his skill is useful for several Bingo missions that require you to enter Fever a certain number of times. Increasing his skill level reduces the number of Tsums you have to clear to power up his skill. The one very nice thing about Pumpkin Mickey is his score which maxes out at whopping 1815 points. So if you manange to level him up and he shows up when you are playing with other Tsums he can definitely increase your score.