Pets.com

Pets.com's 268-day lifespan from IPO to liquidation made its sock puppet mascot the face of dot-com excess. The company sold $619 worth of merchandise for every $1,000 spent on marketing—a metabolic rate no organism can sustain. Like a newly hatched creature that burns energy faster than it can feed, Pets.com never achieved the scale economics its business model required. The sock puppet now teaches MBA students about customer acquisition costs.