Unearthly Caryatids Materialize at Marina City

Chicago has always had its share of caryatids holding up buildings, like the stately females at the Museum of Science and Industry, or the burly males at William LeBaron Jenney's Morton Building on south Dearborn.

Now, however, a quartet of weird new caryatids lay splayed across the floor of a glass-enclosed, unused space at the base of the West tower of Bertrand Goldberg's Marina City.
They are very unlike their earlier counterparts, an almost unnerving hybrid of the Erechtheion and the Outer Limits, looking very much like one of those grainy photos of something on a dissecting table at Roswell.
What are they? Who made them? Where did they come from? Where are they going?
Whatever the answers to these questions, they're unlikely to be anywhere near as good as the story you're currently making up in your own head.