Much as I love Star Wars and Star Trek (which celebrated the 45th anniversary of its first airing yesterday). I have to admit that I've grown completely tired of humanoid aliens. I understand why, in the old days, they were a necessary evil, but, nowadays, there's usually little justification for them. And in literature? They were never needed. I'm much happier with alien beings that don't look as if they could just be a guy in a suit.
So, my question is: what are your favorite non-humanoid aliens? By "non-humanoid," I mean beings that don't look anything remotely like a human being. Adding another head or extra limbs or whatever does not count. I'm talking aliens like Star Trek's Horta, Traveller's Hivers, or Ringworld's Puppeteers. By my definition of "non-humanoid," something like the Hutts from Star Wars would not count, since they're basically just big humanoids with tails instead of legs.