Agreed. In this case, however, it's the Specialist on the New York Stock Exchange. Friends of mine who used to trade, called Specialist on the NYSE, "Criminalist". Apparently they are worse than MMs on NASDAQ.
When a surge of buying comes into a stock like it did with XIN this A.M., The Specialist matches all sell limit orders in the book and the price rises accordingly. If there are not enough sell orders to match buying, the Specialist will raise the price further and beginning selling stock out of his own inventory. If his inventory gets depleted then he is effectively forced to "sell short". that is where the term "sell short" first came from. He is forced to sell stock he doesn't have.
As soon as the buying subsides he will drop his own bid down as far as he can to try to induce profit taking so that he can "get out of debt" so to speak and get his inventory out of the negative and back into the positive. He wants to buy back shares at lower prices then what he was forced to sell them at. This is the slight of hand used that the Specialist can earn himself a tidy profit.