Preheat oven to 350° and line two muffin tins with 20 liners. In a large bowl, combine cake mix and one can of Coca-Cola and mix until smooth.
Divide batter between prepared cupcake liners. Bake until a toothpick inserted into the middle comes out clean, about 20 minutes.
Meanwhile, make buttercream: In a large bowl using a hand mixer, beat butter until fluffy. Add powdered sugar and salt and beat until combined, then add ¼ cup of rum 1 tablespoon at a time until fully incorporated. Transfer buttercream to a piping bag or resealable plastic bag
In a medium measuring cup, combine remaining can of coke, remaining ¾ cup rum, and lime juice. Use mixture to fill 20 solo shot cups halfway. (You may have a little left for refills!)
Pipe frosting in a circle around the edge of each cupcake, then place filled solo cups in the center. Play ball!
Recipe by 5* trending recipes with videos at https://food.theffeed.com/2019/07/02/beer-pong-cupcakes/