Last week, I reviewed Burger King's surprisingly tasty, black-bunned Halloween Whopper. The next day I noticed something strange: My poop was a ghoulish shade of green.

I assumed the goblin-like pallor of my shit was either due to the A1 Steak Sauce-inspired color of the Whopper bun, or the various other pollutants that course through my system at all times.

A combination of surprised and concerned, I chose to pretend that nothing weird was happening, and went on with my day. But now, BuzzFeed points out that people are freaking out over the Halloween Whopper rotting their insides in a similar manner. Mystery solved.

So yes, much like the colorful impression that beets make on your stool as explained in this Portlandia bit, the dyes in the pitch-black Halloween Whopper bun have a similarly transformative effect. Sadly, this festive poo only appears within a day of ingesting the Halloween Whopper, so there's no hope of saving up for St. Patrick's Day.

A (probably horrified) Burger King corporate spokesperson did not respond to a request for comment. At least now I have the email address for when BK's Pumpkin Spice Oreo Shake turns my pee nuclear orange.