Inchworm was a hugely popular toy when I was a kid in the 70’s. I got one for Christmas from my grandparents and I played on it for hours at a time. Inchworm is about 3 feet long and you basically sit on it, bounce up and down to make the worm crawl forward. Inchworm also makes a clicking sound when you turn the wheels. I forgot about it until I ran into this 1970’s TV ad:
I think the Inchworm was a great ride on toy! And made to last too. Mine was given to my younger brother and later to a young cousin before it finally died (the Inchworm, not the cousin!). It saw a lot of rough action that no modern ride-on toy could sustain.
After watching that TV ad I went to check online to see more pictures and found out that the Inchworm is still alive! You can buy a new version made by Radio Flyer. Unfortunately the newer version, like many toys now, is not that great.
If you want to give an Inchworm to your kid, I would try and hit eBay for the vintage 70’s one. Otherwise, you can buy the new version on Amazon here: Radio Flyer The Inchworm