Ghost poop

No, not this kind. (Halloween party treat. See link to recipe below.)

When I had the barium swallow test done, they warned me that I might notice white poop (a.k.a. GHOST POOP) but not to worry. (This happens because the body doesn't absorb barium, so it passes right on out.)

I'm here to tell you ghost poop is a thing.

Made me want to look up barium. A few facts, in case you're interested:

Named after the Greek word barys for "heavy," barium is a relatively dense and reactive alkaline earth metal. It is only found naturally when combined with other elements, and compounds containing barium have a wide range of uses; they are found in rat poison, weighting agents in oil drilling fluids, and the white fluid used to visualize intestines in an x-ray diagnostic test called a barium enema.

• Atomic number (number of protons in the nucleus): 56
• Atomic symbol (on the periodic table of elements): Ba
• Atomic weight (average mass of the atom): 137.327
• Density: 2.09 ounces per cubic inch (3.62 grams per cubic cm)
• Phase at room temperature: solid
• Melting point: 1,341 degrees Fahrenheit (727 degrees Celsius)
• Boiling point: 3,447 F (1,897 C)
• Number of natural isotopes (atoms of the same element with a different number of neutrons): 7
• Most common isotope: Ba-138

— https://www.livescience.com/37581-barium.html 

How to make Ghost Poop.