Francesca4me has created arguably the best Poop Emoji Cookie Cutters on the market, and they come in four different sizes. They include depressions for the eyes and mouth that can be filled with white icing, and the thin lines they cut halfway into the cookie give them the most accurate-looking result.
For best results color-wise, make gingerbread or chocolate dough, or darken sugar cookie dough with food coloring. I don't recommend chocolate chips or nuts, because they get very messy and start looking a little too much like poop. Also great for cutting fondant, and I bet you could use them as a candy bar mold if you did the proper prep.