Artificial Manaborn

Overdraw {6} - Manacharge. Activate this ability only when a forest enters the battlefield under your control. (Add {g} to your mana pool for each opponent) (This ability costs {1} less to cast for each opponent)
"Amazing. The creature I constructed acts just like a manaborn. Now if I could only get the others to accept it as one of it's own..."
- Journal of Unknown Origins