Playdough vs. Poop

Playdough-soft, squishy in hands
Poop-soft, squishy in hands

Playdough-sticky
Poop-sticky

Playdough-sticks to carpet, hard to clean
Poop-sticks to carpet, hard to clean

Playdough-molds nicely into shapes
Poop-keeps falling apart

Playdough-doesn't smell too bad.
Poop-smells very bad.

What would make a kid think one was the other, or at least play with it, rub it in the carpet in the same way, and basically smear it all over????

(Sorry for the grossness, but it's worse in real life. I won't humor you with photos.)