Well I didn't call it a sweet potato. I don't know what it was called. As I was 4 and had delayed language development, I probably didn't call it anything. After googling and seeing the images I remembered having a similarly shaped flutey thing with holes in. It was plastic, tasted funny and reminded me of the yellow school bus that picked up my big brother. Same shape same colour. I probably pushed it around on the floor making vroom vroom noises, unless someone showed me how to tootle on it.