The Blarney Pebble is an item which can be obtained by touching the Blarney Stone during St. Patrick's Week which is located at each of the 9 different BLARNEY worlds (BLARNEY1-BLARNEY9). Players are limited to one Blarney Stone from each BLARNEY world each day.
Once the player obtains 10 Blarney Pebbles, the player may tap the pebbles into their character which will give them a Pet Leprechaun. This will give the player the "Little Green Man" Achievement.
Trivia
If the player taps less than 10 Blarney Pebbles on themselves, a message will appear saying "Legend says that you need 10 Blarney Pebbles!"