I thought it was in reference to the movie "A Cry In The Dark" (also known as "Evil Angels") based in Australia & on a true story released in 1988 with Sam Neill & Meryl Streep in the starring role about this regular woman (Streep) who went on a little sightseeing trip to Ayers Rock with her husband (Neill) & their four young children. They all spent the night there inside camping tents, along with other campers. At nightfall, she put her baby daughter Azaria to sleep in her tent and proceeded to enjoy her evening by the fire with her husband and eventually discovered that her baby had disappeared out of thin air during the night. Distraught, terrified and worried sick for her daughter and in awful emotional pain, she told her husband & remaining children, the other campers and eventually the police that she saw a dingo (Australian wild dog) take her baby but Azaria's body was never found. The Australian authorities couldn`t help but notice some apparent inconsistencies in her story therefore she was eventually accused of murdering her baby herself and had to go to court to defend herself. Her court case understandably attracted a lot of attention, turning a simple investigation into a media circus, with the public divided in their opinion.
That`s where the expression "Maybe the dingo ate your baby!" comes from, I`m convinced of it!
It has absolutely nothing to do with the TV show Seinfeld, only because the character of Elaine said it with a so-called Australian accent!!!
P.S. Why would it be a religious question??? I`m terribly sorry but I can`t see any relevance to religion here...
I hope this cleared out a few cobwebs for you!