I distinctly remember as a small child thinking "Playdough = Potato". And taking a bite of white colored playdough. It tasted like salt. Slimy salt. Vaguely booger-ish in texture and flavor. Not mashed potatoes.
It's Christmas advertising season. I noticed the playdough and other slime funsets are all food related. There was one that was a tub about the size of a coolwhip container. Apparently you add water and the goop inside puffs up to look like some sort of snow-cone material, and you fish out little plastic toys.
And all of it is designed to smell like sweet food stuffs from what I can tell.