Rookie mistake.

Some dude from Missouri posted a sales ad for a catalytic converter on Facebook Marketplace.

His only problem was that he didn't realize his good ol' bag-o-meth, along with a syringe, are in plain sight on the coffee table in the background of the photo.

Detectives promptly paid the man a visit with a search warrant and arrested him on Wednesday.

This sounds like it was the easiest drug bust of all time.

"You can imagine his surprise!! He still had 48 grams of meth and a pistol that he is forbidden to own," Stone County Sheriff Doug Rader said on Facebook.

You know, I'd like to be able to say this is probably the dumbest person on Facebook, but that's sadly (and definitely) not true.

Adding insult to injury, the catalytic converter is not for sale anymore. Press 'F' to pay respects.

You're going to have a buy a catalytic converter from someone else who, at least, doesn't show his meth in the product image.

I think we can all learn from this story, though. Sheriff Rader has some profound advice for all of us interested in selling stuff online in the future.

"Make sure your drugs are not in the background," Rader said.

I couldn't have said it any better myself, Mr. Sheriff.

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