In yet another odd chapter from the US's movie rating history, the MPAA would not let Raiders of the Lost Ark's famous exploding head scene pass without an R rating—until director Steven Spielberg agreed to obscure the phony gore with flames.
Will McCrabb tweeted this piece of Indiana Jones trivia, along with a photo of the unobscured explosion. You can compare it to the video of the scene above.
At the time that Raiders was released, the PG-13 rating didn't exist. Perhaps if it had, we would have seen a less fiery version of the scene in the theaters.
Via Slate, which devoted a video to the subject: