One shareholder got greedy, and all Bloom shareholders are suffering for it today.Well that was quick! Just 24 hours after J.P. Morgan upgraded hydrogen fuel cell company Bloom Energy (BE -8.57%) stock on Wednesday, sending Bloom stock soaring 18% in a day, Bloom stock is turning tail and tumbling back down again.Bloom stock fell 9% through 12:30 p.m. ET. Bloom's ups and downsJ.P. Morgan nearly doubled its target price yesterday, advising investors to buy Bloom stock on the theory that Congressional "48E ta ...