Preheat oven to 350°F. Line two 12-cup muffin tins with paper liners.
In a large bowl, whisk together the spice cake mix, pumpkin puree, eggs, and vegetable oil until smooth and thick.
Divide the batter evenly among the 24 liners, filling each 2/3 full. Bake 18–20 minutes, until a toothpick comes out clean. Cool completely.
Beat the cream cheese and butter until smooth and fluffy. Beat in the powdered sugar one cup at a time, then the vanilla. Tint the frosting bright orange with the gel coloring.
Swirl or mound the orange frosting on each cooled cupcake. Press one mini pretzel stick into the center as the stem and scatter green sprinkles around it like vines.