Regular Time (Adventure Time and Regular Show Crossover)

Madness at the Candy Kingdom, when Princess Bubblegums experiment goes wrong she creates a portal to another dimension (Regular Show's World) and then when tying to fix it she is kidnapped by the Ice King and taken there so Finn and Jake travel there to find them when they run into Mordecai and Rigby at first they didn't see eye to eye but now Mordecai and Rigby decide to help defeat the Ice King with the help of some of their friends, in an all star event!!!