The irrational exuberance of Pets.com, which burned through $50 million in venture capital in nine short months, will no doubt be told as a cautionary tale to our children around the campfire. What other investments are scary enough to give venture capitalists nightmares? Venture Beat has helpfully condensed Inside CRM's list of the 20 worst offenders, which includes notorious failures like Web currency Flooz and Amp'd Mobile. [VentureBeat]