This one's just mean. I accidentally gaslit a white belt.
Today I was rolling with a white belt. He's like half my age, in pretty good shape, and learning pretty quick. The move of the day is straight ankle lock, and our instructions during rolls was to just hunt submissions nonstop. So I let this white belt take my back, I grab his feet and cross them, then go for the straight ankle lock. I didn't quite get it.
The rest of class he was trying to figure out how he crossed ankles, because he knows better than to cross his ankles. At the end of class, I told Professor, "I let him take my back, grabbed his feet and crossed his ankles, and then went for the straight ankle lock.
The white belt heard me talking to Professor, he goes, "THAT'S how they got crossed! I thought I knew better than that!"