Rain Biome

Rain Biome is a Biome to which Forests occasionally turn into. This biome hosts a whole new brand of surface dwelling monsters and variants to old monsters as well. It doesn't affect any blocks at all and whether it makes water levels rise or not is unconfirmed.

Goldfish are capable of moving on land and "walking" on their fins during rain.

Monsters

 * Umbrella Slime
 * Flying Fish