A co-worker's boyfriend once showed me their beloved woma, which was actually a ball python. (A normal, not even the woma morph, if that's what you're thinking. They thought this was a real woma, from Australia.)

I never called to inquire, but I saw an ad posted on the bulletin board at Petco for a "boa python" for sale.

Years ago a woman wanted to give me her ball python because it had outgrown its enclosure and was too aggressive for her to handle. I went to check it out and it was an African rock python.

One time a man thought he owned a Brazilian rainbow boa. It was a retic.

There's so many more. I worked in pet shops from my 18th birthday until I was 23 or 24. Don't even get me started on the mis-identifications I'd see in shipments from the distributors...