noun. In the flash animated series of Homestar Runner cartoons, a non-existant wonder that Strong Bad uses by looking into a paper bag. Homestar Runner has hopes that he will someday be allowed to see the Thing In A Bag, and does errands for Strong Bad to curry his favor.
HS: What are you doing?
SB: Hanging out at The Stick, looking at a thing in a bag.
The feeling that one has when they see something so attractive that it takes courage to look directly upon or in to, knowing that once you do, you won't escape... yet you won't have a problem with that.