We Demand a Shrubbery!

Enchant target player
At the beginning of enchanted players upkeep,
they may pay {1}{g}{g}, if they do, you create a
0/3 green Shrubbery creature token with defender.
If enchanted player doesn't pay {1}{g}{g}, add X
mana to your mana pool where X is the amount of
mana enchanted player controls.