Around this time last year Burger King’s black burger hit stores in Japan for the first time only to be received with a lot of hesitation. But they’re back – and this time to ‘celebrate’ Halloween.

Yet, there’s a little issue.

Unlike last year, when squid ink was added to the burger for the black effect, The Halloween Whopper has A1 sauce baked into the bun. Sure.

But the real problem is that some ingredient in said black bun is making people’s poop neon green. And they’re taking to social media to share their stool.

There has been a suggestion that it could be caused by a liquorice property. That’s a whole lotta liquorice.

[source: mashable]