That is dog shit

Across the pond, our American friends have a chocolate bar that looks exactly like dog poo if you microwave it.

Naturally, a prank has evolved where you follow those steps and proceed to eat the melted candy bar in front of your unsuspecting victims.
But this chap decided to reverse the whole thing when the Baby Ruth/dog poop prank got old and everyone knew about it.

Yes, he got real dog poo and made a co-worker to take a bite.