"Jingle Bells, Batman Smells" is one of the most significant documented viral songs among English-speaking children. Because it was spread as an oral tradition for its first quarter-century, many variants emerged. Tom Scott quizzed 64,000 people on their recollected version of the song, with some surprising results.
His thesis is that The Simpsons had a strong role in creating the current canonical version. However, it's clear why "Robin laid an egg" is a much better line than the competitors. First, it literalizes Robin as a bird. Second, is misgenders Robin (already a gender neutral name) by saying he laid an egg. Third, it's a thinly veiled poop joke to many little kids, who are always going to like a poop joke. Thus endeth my dissertation on why "Robin laid an egg" is the vastly superior one and true version.
Don't get me started on "I'm Popeye the Sailor Man."
Image: YouTube / Tom Scott