Frank Belknap Long's "The Trap" (short story, first contact, free): Life can exist as pure shape too!
Story happens on a far off world - an interstellar refueling station, with two attendants, of a star faring humanity. An unusual alien ship has arrived with which all previous attempts to communicate have failed. But attendants of the station will "meet" the aliens.
- Incomprehensible aliens: Terry Carr's "The Dance of Changer & the Three" (download).
- Vampire-derivations: C L Moore's "Shambleau" (download) & "Black Thirst"; Eric Frank Russell's "Sinister Barrier".
Fact sheet.First published: Astounding, May 1945.
Download full text as part of the scans of Astounding issue where it originally appeared.
Among the stories from Astounding/Analog issues edited by John W Campbell, Jr.
Related: First contact fiction.