This was an amazing sculpture that subtly reacted to you via sensors as you walked below it. (And then there were sensors that would react to that movement above) Those protrusions that look like feathers were actually finely cut plastic. And despite its resemblance to jelly fish, my daughter agreed with all of us that it was rather lovely. (She has a jelly fish phobia. Even though we live in Idaho and she's only been to the ocean once. Go figure.)
Just editing to add that this was created by Phillip Beesley. You can read a bit about it here and even download an mp3 of the artist discussing the work!