Sometimes when you need a Terminator, a crazy puppet backpack will do. Sometimes, you've just gotta go a little further. And when it came to Terminator 3, the effects team took the second option and basically built actually Terminators. Almost.
There's no denying that the Xenomorph queen is terrifying in Aliens, but she doesn't seem quite has bad when her lifeless head is just sitting on a table in its earliest form, not quite sculpted into the horrifying finished product. She's still no looker, though.