It is the baby in a car seat. The car was a 2-door sports car. Baby and car seat not likely in the back seat. one would have to be a contortionist to get the baby in and out. My guess.
At least you’re trying to make a reasoned guess, but the baby wouldn’t project a silhouette like that, it’s that of an adult. Anyhow I don’t really like flogging these conspiracy whacko theories and all, but there it is.