Investors Apprentice, fwiw:
My thought was the same as rnmenterprises: Someone tried to place an order for 0.00009 and skipped a zero.
re: "should have executed at the best price," in an honest market, absolutely. Thus my sarcasm, "Wonderful World of MMs.."
If you think about how MMs work, it makes perfect sense. If I sell 100 shares of AAPL at the same time you buy 100 shares of AAPL, I don't sell directly to you. The MM buys my shares and then sells them to you, typically a penny or two higher, the differential being their profit.
In this case, someone offered to buy some WNSH at 0009. The first MM that saw that probably snapped it up instantly. 500k block, so only $400 profit (500k * (0009-0001)), but free money, so why not.