Have seen these sort of tactics on both sides of the sheet...

Have seen these sort of tactics on both sides of the sheet before. Typically they find a stock with a very short list on the buy side and place an outrageous bid like this. If the market moves suddenly, sometimes the buy side gets swallowed up quickly as holders dump "at market price". With luck they pick up some very cheap shares.
Motto: never place orders buying or selling "at market price"