HalloweenPumpkinster and Frankenster were offered in the Shop as Special Monsters during October, 2012. Pumpkinster is unique in that he gains experience particularly slowly compared to most other monsters. Even though the Halloween promotion was over for 2012, Frankenster can still be obtained as a prize in the Gold Lottery, and Pumpkinster can now be obtained anytime in the shop for 30,000 gold.
ThanksgivingDuring early November of 2012, Pilgrimster became available as a Special Monster. Rather than being available throughout the entire month, Pilgrimster was removed from the shop on Cyber Monday. Pilgrimster is now available in the shop all the time for 260 crystals.
Winter 2012Gameloft began releasing winter-themed Special Monsters and Buildings in the Shop during the first full week in December. Pinester was released during the third full week of December and was removed from the shop in early January: the only special monster through the event. Though there are probably no plans to remove them from the shop, Starster and Reindeerster are two other winter-themed monsters that were released during the first and second full week of December respectively.
For Halloween 2013, they added Frankenster as a special monster, and lowered the price of Pumpkinster to 3,000 gold. They also added Huolongster for Chinese New Year, Cupidster for Valentine's Day, Cloverster for St. Patrick's, and Pinester returned for Christmas. They lowered the price of Stonester and Rhinoster.