The Little Mash Theory
In Season Four of the show, we met treasure hunter and owner of Little Mash Island, Gary Clayton. His tiny piece of land is located a few hundred yards north of Oak Island, which he thinks was made by 18th century naval commander Lord George Anson.
Source: History Channel
Clayton told Rick and Marty he believes there’s a tunnel between his island and Oak Island and that the treasure is buried somewhere underwater. He believes several hundred tons of gold are scattered in chambers underneath his island (although he has little proof to back it up).