Could someone explain what just happened like I'm 5?
Fog of battle. The closing cross auction price is $695 (what the indexes bought at least 60 million shares at), but the instant market price a couple of seconds before the market closed was several percentage points lower. So there's a big confusion about what will set the price for expiring options. Also, you would expect the closing cross auction price and the instant market price to converge at the close of trading. But this didn't happen.
Very exciting. Very confusing. A bit disorderly.