Knopf-Doubleday celebrates Poetry Month with a poem a day. This piece by Mark Strand, they say, isn’t quite a poem but neither is it not a poem:
The Triumph of the Infinite
I got up in the night and went to the end of the hall. Over the
door in large letters it said, “This is the next life. Please come
in.” I opened the door. Across the room a bearded man in a
pale-green suit turned to me and said, “Better get ready, we’re
taking the long way.” “Now I’ll wake up,” I thought, but I was
wrong. We began our journey over golden tundra and patches
of ice. Then there was nothing for miles around, and all I could
hear was my heart pumping and pumping so hard I thought I
would die all over again.

I guess anyone can call anything whatever they want. However, as an old Eng, Lit major, I would possibly allow this as blank verse but in my mind, it is simply a piece of provocative (as in “etherially” thoughtful) prose.
It forced me to read it several times for impact.