Rumors are surfacing of a new kid friendly monster theme coming mid next year. It appears to be Scooby-Doo based on postings from iso3200 on Brickset & Miniworld on Hoth Bricks. Potential sets mentioned include the Mystery Machine van, a haunted castle and another set featuring a Swamp Creature.
This seems credible since LEGO likes licensed properties that have a media component such as a TV show or movie. As it happens to be, there will be a new Scooby-Doo show coming next year on Cartoon Network called, Be Cool, Scooby-Doo! Character Building currently has the license but their licensing period may be ending soon. As always, until confirmed by LEGO, treat this as a rumor.
Via The Brick Fan