Costume: Don't Blink Jewel!
I have heard of dangerous conventions, but a convention where no one can safely close their eyes, that is a bit much, even for me.
This is an amazing weeping angel statue in honor of the Doctor Who episode, Blink, worn at Dragon*con this year. I think I might have freaked out if I saw one of these in a hotel hall.
Unfortunately for Jewel (Firefly/Stargate Atlantis), she blinked.
(via drhaggis (1/2) and Ray Radlein on Flickr