Pets.com

Pets.com had inarguably one of the best mascots of all time. Sadly, their business was not as strong as their sock puppet's appeal - delivering giant bags of low-margin dog food turned out to be a generally unprofitable endeavor in 2000.

Pets.com had a flashy IPO in 2000 then filed for bankruptcy nine months later. It was fashionable in 2000 (and again, for a while until recently) to have a business where you lost money on every transaction. For some reason, public markets were less effusive about this model during the dot-com bust and all that remains of pets.com is fond memories of their spokespuppet.