Postulated by a non-freckled human. The theory proposes with enough sun exposure a freckled person's freckles will eventually connect - seemingly making them very tan, but in fact just making them a giant freckle. This theory has not yet been proven, only tanning creams have helped self-loathing freckled individuals achieve this.
Steve: Did you see Martha the other day?
John: Yeah she's been on the beach every day; testing out the freckle theory I presume.
Steve: She sure would make one sexy giant freckle!
John: True story.