Rain Cloud Decoration
Like other decorations in ̶0;Treasure Isle,̶1; the Rain Cloud doesn't have any abilities or effects beyond its aesthetic appeal. You can place this one-by-one decoration anywhere on your island. It appears as soon as you finish collecting the Tiki Statues Treasure set. You can't sell the Rain Cloud or give it as a gift. You can acquire it only by completing your collection.
Tiki Statues Treasure Set
The second collectible treasure set in ̶0;Treasure Isle,̶1; the Tiki Statues set consists of five separate pieces: the Mountain God, the Wind God, the Sea God, the Forest God and the Rain God. You can find the Tiki Statues on Sunny Shores, the second island you encounter, and the first that requires a Machete. You can dig up most of the statues at a cost of 75 energy each. These statues are considered uncommon in frequency. Once you find the statues, you'll receive the Rain Cloud and 2,500 gold.
Rain God
Unlike the other four statues, the Rain God isn't buried. This statue is the most difficult to obtain, since you can only get it as the reward for completing Fire God Mountain. This special island was released in June 2010, and has 14 levels, each with one treasure. The goal is to find the treasure by digging as few times as possible. Fewer digging attempts grants you better rewards upon finishing the area, but you will receive the Rain God no matter how poorly you do.
Considerations
Prior to June 2010, the Rain God was buried, just like the other Tiki Statues, but was the rarest and most difficult to find. Some players were entirely unable to find it. During this period, if you emailed the development team about your inability to find this item, it credited it to your account, sometimes adding some Island Cash as well. This method for acquiring the Rain God no longer works, as of October 2011.