The jump is due to technical reasons.
In essence, you have way too many people rushing to short sell Sears as they anticipate that the price will go down. Short selling assumes that someone is willing to borrow you stock so you can sell it, at some point you'd need to return that stock. In order to return it, you need to buy it from someone, and since Eddie owns almost all shares that float right now, if he decides not to sell it to you so you can cover your short position, you need to go to someone else and attempt to buy it.
The problem is that, if for whatever reason the stock goes up that day (e.g., Hudson Bay announces that they may buy Macy's), there is a mad rush of people who are rushing to cover their short positions (fear). So, now everyone is chasing that one guy that sells stock (Eddie is not selling his) and people start to bid up the price for that small amount of stock that's floating around.
That bidding, that mad rush, is pushing the stock price up, Eddie still does not sell, and the price keeps going up. the more it goes up, the more short sellers panic or simply try to cover their positions or take profits, so the price continues to goes up.
So, the problem is that there is not enough stock floating around (float) and Eddie is comfortably waiting and sitting on his stock until the stars align and he's ready to do and execute whatever he really planned to execute (nobody really knows this as of now)...
I hope this helps. Do not short it...