The first player to fill up his 6-space enclosure gets the Catta enclosure and places 3 coins from the bank on it. If it is the owners turn he can skip this turn but has to pay one coin from the enclosure to the bank. If there is no coin left on the enclosure he cannot skip his turn. If at least one coin is left on the enclosure by the end of the game the player gets one additional scoring point.
For more information: http://boardgamegeek.com/boardgameexpansion/110922/zooloretto-catta