sockpuppet
noun
An online identity created, and used, for purposes of deception. A sockpuppet purports to be an independent party that supports, approves of, or agrees with some agent (a person, organization, agency, or state), but is in fact created and controlled by that agent, and has no independent existence. Common uses of sockpuppets include plausibly deniable hacking or information operations, provocation, and astroturfing (creation of the illusion of grassroots support).