Mammoth Books presents Substitutions

Taken from The Mammoth Book of Best New Horror 22, edited by Stephen Jones.

As Smith recalls: "This story came about in the simplest way, the way I always enjoy most - something happening in real life that makes you think 'What if?' "Our household gets a lot of its food via an online delivery service, and one day when I was unpacking what had just been dropped at our house I gradually realised there was something...not quite right about the contents of the bags.
"There's two things that are strange about that experience. The first is that - given that every household is likely to buy at least some things in common - you don't realise straight away that you've been given the wrong shopping. You don't immediately think 'This is wrong', more like . . . 'This is weird'. The second is how personal it is, gaining accidental access to this very tangible evocation of some other family's life. You can't help but wonder about the people the food was really destined for.
"In real life, I just called up the delivery guy and got it sorted out: but in fiction, you might tackle things slightly differently . . ."