8. Macaulay Culkin - The Talkboy (Home Alone 2: Lost In New York)
The second Home Alone movie sees Kevin McCallister (Macaulay Culkin) prominently using a Talkboy, a nifty cassette recording device which he uses to outsmart the movie's adults, and which upon first glance simply seems like a well-placed product placement.
Except, the Talkboy didn't actually exist and was instead invented for Home Alone 2, with Fox commissioning Tiger Electronics to design a plausible prototype, which they achieved in just three weeks.
Though the version used by Culkin in the film didn't actually work, he was nevertheless allowed to take it home at the end of shooting as a gift.
But the story gets better, because Tiger was ultimately given permission from Fox to create the Talkboy for real.
Though the initial manufacturing run sold poorly because it wasn't capable of voice manipulation as in the movie, the second Deluxe model added this feature and was a massive commercial hit.