This is a manufactured event

From SeekingAlpha:

On a daily basis, shorts use computerized trading to control the direction of the share price. At opportune times, the shorts overwhelm the buyers (bid price) of the stock by selling short large number of shares to drive the share price down and to eliminate the buyers for the stock at that given time.
Now the shorts can buy back some of the shares they have shorted at lower prices including some shares where longs have put stop-loss sale orders to protect against downside losses.