Peanut Butter and Chewing Gum
One time when I was 8 I started eating peanuts while I was chewing on gum. The peanuts seemed to dissolve the gum and it basically disappeared into pink peanut butter.
Fascinated by the experience, but old enough to know better, I did it again when I was about 12.
Since then I’ve never been able to shake the feeling that the pink muck must still be stuck in some nether region of my colon.