Astral Cornucopia enters the battlefield with X charge counters on it.
: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.
2/1/2014 If you choose 1 for the value of X, Astral Cornucopia will cost to cast and enter the battlefield with one charge counter. If you choose 2 for the value of X, it will cost to cast and enter the battlefield with two charge counters, and so on.
2/1/2014 The last ability is a mana ability. It doesn’t use the stack and can’t be responded to.