If you were looking for the trope about people who control puppets, look here.
For people who control other people, see here.
And for the trope formerly known as the novel, look here.
An author/perpetrator of an Alternate Reality Game is called a puppetmaster. In most cases, many puppetmasters are involved in a game, because there is a good bit of work to be done, widely divergent work. Such tasks include burying clue boxes on a GPS coordinate, having cryptic cards printed and distributed, or playing an in-game character for a recorded message.
The most widely known Alternate Reality Games are the A.I. tie-in "The Beast" and the Halo tie-in "I Love Bees." It is not a coincidence that the owner of record for almost all of the Web sites in "The Beast" had the surname "Gheppetto". (Further, both The Beast and I Love Bees were produced by the same team: 4orty2wo.)
"The Puppet Master" is also an alias used by Phillip Masters, a reoccuring supervillain in the Marvel Comics fictional universe. He mentally controls his victims by sculpting their likeness from a special radioactive clay.
Lastly, Puppet Master was a cult horror film from Full Moon Pictures which spawned nine sequels of varying quality.