Tree of Wisdom
The Tree of Wisdom gives tips as you give it Tree Food for its growth. You can grow it up to 1000 feet, and (if you feel like it) to infinity. However, it will stop changing it's appearance eventually, as well as running out of tips for you at some point. You can buy the Tree of Wisdom in Crazy Dave
's shop for $10,000. It has an unique personality, being very thankful when you feed it with Tree Food and praising you for your genius.
A large Tree of Wisdom