Mikey's plan to let Donnie indulge himself and still be a part of the team, is to let him play a support role! With the replicator perfected, Donnie can mass produce any parts he needs to build an army of drone that can serve as eyes and ears all over the city, and helps his brothers on patrol missions. On top of that, he's also controlling Metalhead, to act as a fourth team member in his stead. Donnie has become a massive information hub, allowed to stay home and grow as fat as he pleases now, much to Mikey's delight.