Chapter Seven: The Bathtub - S1-E7
Factual error: When there is a pan closeup shot of the walkie-talkie the boys are going to finally talk to with the sheriff, there is a book called Great American Ghost Stories by Hans Holzer on the shelf to the left. That book was published in 1990, not in 1983, the year of the episode. (00:18:30)
Chapter Seven: The Bathtub - S1-E7
Factual error: High school basket ball courts didn't have a three point line until the 1987-88 season - not in 1983.
Chapter Seven: The Bathtub - S1-E7
Continuity mistake: When Mike and Lucas notice a van pulling out of a side street and coming to them, the sky is blue, but in the next shot, it is orange. (00:04:03)
Answer: The body was fake, made by the scientists at Hawkins Lab in an attempt to cover up his disappearance and the existence of the Upside Down.