A sock puppet is an extra account created in addition to the user's normal account, especially with abusive purposes.

A sock puppet is an extra account created in addition to the user's normal account, especially with abusive purposes.

On Stack Exchange, one abusive reason for sock puppetry is serial voting, especially upvoting own answers.

Users found to be abusing sock puppets will have such accounts deleted and their main account will be suspended or deleted.

Note that having more than one account for a legitimate purpose is permitted: