Euphorbia Trigona - African Milk Tree
A popular and fast-growing succulent, the African Milk Tree is a favorite among plant collectors. Care for it is similar to other succulents - allow it to get plenty of bright, indirect light (some partial sun is fine, a south facing window is ideal). This plant can do well outdoors in the summer. Water when the soil has completely dried - this is a very drought tolerant plant. Make sure you have a well-draining soil.
African Milk Trees can grow up to 2 feet a year, but have relatively small root systems, so make sure you have stakes ready to prevent it from tipping over.