sasquatch poop

When you take a dump and you feel it, hear it and smell it but when you turn around there is nothing there.

When you look for it it is never found, leading to some not believing its existence.

Up north it is known as an "Abdominal Snowman Poop", and in other countries "Yeti Shit"

Son: look Mommy!! I used the potty!!!
Mom: Good job honey, I'm so proud!! Let me see!....wait the bowl is empty...
Son: i swear I did it, Mommy
Mom: It does stink in here... But I don't believe you did it
Son: Really mommy, I did it must have been a Sasquatch poop..
Mom: There's no such thing..
Son: mom, don't be a skeptic, they are real
Mom: Go to work, your late.