This is what we call a "dead cat bounce"*
Basically, it'sa gain that comes from all the people that buy into shares that they think have gotten to their lowest point. At that time, because of a whole heap of purchases, you get a slight uptick in the value of stock.
Of course, the problem is that all these arseholes then go and pat themselves on the back for buying at the right time and sell out, which devalues the stock even more, and then pat themselves on the back for selling out at the "right time" because they got in before the REAL downfall (which they actually caused).
The smart investors buy in after the DCB.
* It is derived from the notion that "even a dead cat will bounce if it falls from a great height".
Thanks, Wikipedia!