I saw a picture and description of Sigourney Weaver playing a character in one of the prequels. She was some sort of bounty hunter I think, and had an antenna sticking out of her head (no joke). What was that all about, and why isn’t she in the prequel?
First I’ve heard of it. Sure it wasn’t someone’s photoshop joke?
No, I saw one of those cardboard cutouts of her in Borders around when Episode II came out. I think she was blue, and bald.
I’m thinking your mind is playing tricks on you.
Or you are the victim of a friend’s cruel joke.
By your description it sounds like Aurra Sing (bounty hunter with an antenna) which was not played by Sigourney in her one second part in Epi 1. Rumor had it that she would have a bigger part in Epi 2 but that character was changed entirely.
So, with all due kindness… you are mistaken.
Aurra Sing was played by Michelle Borriague.
Also, Aurra Sing is NOT blue.
The female bounty hunter in Episode II is Zam Wessell (I forget who plays her), and she’s a changling. She usually appears as an attractive humanoid female, who changes to an alien. (I forget the species name)
Sigourney Weaver was sitting right next to E.T. and Willow.
I thought she was the female Wookie.
Don’t know what she played in the movie, though. 
Um, she was eaten by the … alien predator?
And wasn’t Sally Struthers going to play Jabba The Hut?
I hear Lucas is planning to break continuity within the Star Wars universe again by having the Borg appear in the next prequel – two centuries before the citizens of the galaxy were supposed to have met the Borg for the first time!
The same thing that happened to James Caan in Thunderball.
Willow was in TPM, too.
I think the OP means this chick:
http://www.starwars.com/databank/character/slymoore/eu.html
But it’s not Sigourney Weaver.
Some years back in Time magazine was a picture of rescue workers picking up a female Olympic runner, who had crashed on the track. There was some controversy, because the picture had been digitally retouched (one of the first cases, as I recall) to remove a portable radio antenna which appeared to be sprouting from her chin.
I remember thinking that the runner, who was jutting her jaw forward in a pain-filled grimace, looked like Sigorney Weaver.
Perhaps this is what you are thinking of?
Testing my memory: The runner was Mary Decker-Slaney, knocked down off the starting block by Zola Budd.
I don’t remember much of a controversy. I seem to recall that nobody noticed when the picture originally ran in its altered form, but that Time did a page on the alteration in their “year in pictures” wrapup a few months later. They explained that they thought it was a good enough picture to warrant the change, and that it didn’t materially impact the content of the photo, but that it was still worth mentioning and discussing in terms of the ethics of photojournalism.