wow! ive never seen one like that. its got to be worth something.i would bring it to a currency and coin dealer just to get their take on it. great find!
U.S.currency is printed in 3 stages.The first being the back,it is allowed to dry.Then the front,same thing.Last but not least the last printing is the serial numbers and the treasury shield that are printed in an overprint press.Yours looks like it got offset in the last printing(ie-serial numbers and tresury shield).Definitely worth more than face value.How much? Who knows? I think i'd hold on to it for a while.It's not going to lose any value,being an error note and all.BTW-it doesn't look fake to me.I can clearly see a few of the security features on your bill.The watermarks and the strip are both visible.Be wary of dealers,ask what they would sell it for if it were thiers to sell.just because they deal doesn't mean they're word is gold.Definitely DO NOT SELL TO A DEALER!!!!
I hate to say this but it looks like you found "funny money" as the olive branch in the offset bill is totally wrong for a twenty dollar bill. Compare a few more twenty dollar bills to it and you will notice a slight branch variation. I would take the proper action in reporting the bill and where you got it from.
Plugger, Bills are printed in three stages like digg said. Hold the bill up to a light and look for a Andrew Jackson watermark. It will be the same face looking right in a watermark if its real. Counterfeiters often bleach out a $10 bill and print over it to make a Twenty. But it will have a $10 watermark face looking left of Hamilton's.
A misprinted $20 bill just sold at Orlando auction for $25,300. I have the Jan. 8 news arcticle but don't know how to scan. I will try.
There are numerous paper money errors, I'm sure any bank will be able to authenticate it for you as far as being counterfeit, Keep us posted, HH Art...