The existence of Spongebob and his strange friends is the result of radiation from nuclear arms testing that was performed on the Bikini Atoll in the late 40's and early 50's. Since
Spongebob Island Painting Prints - Etsy
The Bikini Atoll island in the new intro looks awfully similar to "We Gotta Get SpongeBob Back". | SpongeBuddy Mania Forums
Bikini Atoll (SpongeBob) by Challenger153 on DeviantArt