Today’s cool kanji isn’t actually a kanji! I’m so excited about this! Aren’t you!? It’s called the 米印（こめじるし） and it’s used in Japan as a marker of clarification/warning. It’s called 米印 because it looks like the 米 character if you rotated it 45 degrees. You often see it below a chart used to explain something. You also see it on instructions warning you to do something a specific way. I just bought a desk and had I paid attention to the 米印, I would have realized I didn’t need to hunt down a weirdly shaped screwdriver – one came with the desk.
One of the coolest things about this character is that if you type in こめじるし and then 変換（へんかん, change from kana to kanji） it, ※ will be one of the options. On Windows, it changes the whole thing, but on my Mac it only changes こめ. I need to experiment further on Windows.
Another cool character is the Japanese post office mark – 〒. Also not a kanji, but like 米印 it can be accessed by typing in equivalent kana, in this case ゆうびん.