Oldhoopster

The only thing that would be close is a half dollar struck on nickel stock (circled in red). Since nickels aren't clad, you should be able to easily confirm this by looking at the edge. (I saved a pic of the following table from a post on another forum and don't know the original reference.)

Can't see anything based on the pics. Did you check Www.doubleddie.com Www.varietyvista.com If you're looking for doubled dies in change, those should be the first sites you check. Plus, there is a lot of good info on how doubled dies occur

I love the method he uses when he doesn't get what he wants. Rant, carry on, and say bad things about the person (company in this case). I'm sure if you keep this up you'll convince everybody here that you're right I think my kids learned that this wasn't a good technique when the they were 4 or 5. Maybe they could give you some advice

Did you use a gas or electric oven?

Agree. It's a linear plating blister. It's not unusual to see these on the copper plated cents of the 80s

Once again, how did the 6 “S” mintmarks get flattened during the minting process? Do you think they could be random circulation marks? Have you considered that some of the members could be very knowledgeable of the minting and die making process? Is it possible that they’re telling you that this can’t happen at the mint is because they understand the minting process and know it can’t happen at the mint? Or do you think everybody here is guessing? Did you bother to try to do an overlay to show that the S matches the size and shape of those used on 1978 cents (proof only issue)? Wh

How did the 6 S mint marks get flattened? Can you provide a plausible explanation of how this could occur during the minting process? Do you think it's die related? From the striking process? The planchet? Still waiting to hear your theory/explanation.

It appears to be a lamination error, but the condition is pretty bad. Cool for a buck +/-, big mistake at $50 IMO

Here is a list of the varieties that NGC will attribute. I don't see any 2009-D Cents on the list. https://www.ngccoin.com/variety-plus/

I’m active on CT and IMO, there is a lot less Moderation than PCGS/CU (haven’t been here long enough to have an opinion). One thing I noticed on CT, however, is you’ll be instantly banned if they discover you open a second user account. No questions, no appeals, POOF! This is what may have happened to the people complaining about CT being unfair.

Nickels are not clad, they are a solid 75% copper 25% Nickel alloy. Your coin is stained/environmentally damaged, or has some glue/adhesive or other substance as others have said. It is not an error of any kind One of the keys to identifying errors and varieties is knowing the minting and die making process. You've received answers from members who are very knowledgeable of the process. Here are some links to get you started https://www.usmint.gov/news/inside-the-mint/how-coins-are-made-coin-production-terminology https://www.coinnews.net/2013/09/13/how-the-philade

See if you can find an exact match on: www.varietyvista.com www.doubleddie.com

So you're saying that the Mint employee responsible for adding the mm to the die hit the punch 25+ separate times? Or do you have another theory of how there could be so many OMMs on the coin?

Absolutely damaged

It's called split plate doubling. The copper plating split during striking exposing the zinc core, so it's not really doubling.