A needlessly complicated plan to accomplish a simple task.
Creating an elaborate scheme involving things like lasers, explosions, rope ladders, poisoning and painstakingly crafted lies to make things more cool, interesting and exciting when all could be solved simply by telling the truth, getting the key or using the back exit, etc.
Cool for the sake of cool in effect (often used in movie plot explanations or sitcom plots).
The name Tom Sawyer Plan comes from Huckleberry Finn where Tom makes an elaborate scheme to free Jim from the plantation when they could have just gotten he key the whole time.
Sheldon Cooper on the Big Bang Theory's web of lies to avoid seeing Penny in RENT, which build on each other until he has to go on a weekend trip, hire an actor and keep up an elaborate fake back story to get out of seeing one play.