An imaginative dialogue by science fiction author Terry Bisson. It first appeared in the "Alien/Nation" collection published in the April 1991 issue of Omni Magazine.
The story is an exchange between two mechanical aliens, one trying to convince the other that thinking meat has been discovered. A la Who's on first, the second alien is slowly and horrifyingly convinced that these ugly bags of mostly water, these carbon based units, these Homo sapiens sapiens, these humans, are actually sentient meat (and mortal no less). The aliens decide that such bizarre creatures are best left alone.