Take a look at this striped dress. I guess you could pass it off as a prisoner costume since it is black and white striped. It's a bit long, but certainly more appropriate that those sexy prison costumes you see for sale at stores and online.
And below is a used lab coat, a real one with an actual person's name and degree stitched into it. I have nothing against using such an item for a mad scientist, doctor or whatever costumes require a lab coat. It's amazing, though how many of these turn up in these racks.
There are certainly other weird and questionable items in what Goodwill calls the Halloween racks. This is just scratching the surface. In years pasts, I've blogged about this, including here, here, and here. Same thing happens every year.
And I think I should mention wedding dresses in the racks as well. These seems like something someone might use to be the Bride of Frankenstein or any gothic character, but I personally would have a hard time wearing these out. If I personally wanted to be a bride character, I would use a white graduation gown, and make it look like a bridal dress. It's be a lot less bulky and easier to wear to more than one event, if that is what you have planned, and easier to repeat for each event than making a toilet-paper bride costume. The toilet-paper bride would also be problematic if rain is expected in your neighborhood on Halloween night. In my neighborhood, you never can tell what the weather in late October will be like. Right now it's still summer-like weather, even though the first day of fall was two days ago. Pretty typical whether in this area.
BTW, I still haven't decided on a costume. It's till only September after all. But I do have some things in mind and will let you know another time.