We did all sorts of things as kids to make our bicycles cooler. Decals. Sparkling banana seats. Streamers on the handlebars. Baseball cards in the spokes to simulate the purr of an engine.

The latter is the idea behind this rather extravagant attachment offered up by Mattel in the 1960s. While it appears to look like a tiny two-stroke motor, it's merely a noisemaker. It "looks and sounds like a real motor." But it's not. Stick two D batteries inside, slap it on the back of your trike, and you can fire up a roar. As the slogan proclaimed, "You can tell it's Mattel… It sounds swell!"

At the time, five bucks was a lot for a sound effect. Still, it undoubtedly preserved some baseball cards that are worth a lot more now. And today, the item is fetching $100–$250 on eBay. 

So, was anyone lucky enough to have one of these?