I think you're about to see the
largest margin call in Poloniex history.
Some guy named Cagara opened a 100btc short on Bitshares around 0.00002700 sometime around Sept 23rd. He thought the price was going to go down to 0.00002200 but it didn't, the price went to 2450 or so then recovered to 2700 again while his short is still open.
Now this guy has to buy 100 BTC worth straight off the sell wall or wait for the price to go higher and get margin called. Depending if he manually covers his short or waits to get margin called, the price is immediately going to go somewhere between 2900-3100 relatively soon.
There's also nobody selling for him to cover his short either because a double sell off wave just happened. He keeps trying to dump into buy support to stop the rise just digging himself deeper in the hole: