You can buy a crap load of Mesa at the low price and it will cause the price to rise a lot in one day. Now that you are sitting on all those shares you can "borrow" more shares of Mesa from a broker on a short position. Now you are holding purchased shares and "borrowed" shares from a broker that will need to be repaid at the sale price + a commission. Since the stock is still cheap and volatile you can dump all of your purchased shares to cause the stock to dive bomb and be able to cover your shorts with a nice profit.