I was on a geological excursion with unfamiliar people. They were students or tourists whatever, they didn't seem to know a lot about geology and I lectured them why the deposit we were looking for actually had to be below sea level and not where we were walking. I was aware I was actually making all this up and know very little about geology. No, actuall Alice reminded me of that so I wouldn't make a fool out of myself. But luckily nobody objected or asked any questions. Anyway we were coming to a rocky shoreline, black magmatic rocks with next to no vegetation. Directly at sea level was a dark band of rock and I declared this is what we've been looking for. The rock looked like coal, black and very brittle. I asked for a hammer and one of the people gave me an ordinary hardware store hammer but told me not to break it. Tupper complained in mindvoice that was not a geologist hammer but better than nothing. I started to scrape around in that rock formation and unearthed a square black rubber plate the size of a hand. That was odd. Somebody remarked that might be a fossil what an idiot. That was clearly modern and man-made. After a few hammer strikes a large layer of rock broke off, revealing two rubber boxes containing the black rock we had been looking for. It was only in those two boxes and they had a note attached saying 'you've been pranked'. Somebody had buried them just to fool geologists. Somehow this was the funnies thing ever, I wasn't even mad. Well-played.