Snake oil is an expression that originally referred to fraudulent health products or unproven medicine but has come to refer to any product with questionable or unverifiable quality or benefit. By extension, a snake oil salesmen (joebum) is someone who knowingly sells fraudulent goods or who is themselves a fraud, quack, or charlatan.
Don't forget to check out GC61NH9 "Catch the Cache" also located in the park!
Congrats to Zeek_70706 for the FTF!