You may pay WUBRG rather than pay this spell's mana cost. If you do, X is 5.
Bringer of Green Zenith's Twilight enters the battlefield with X +1/+1 counters on it. If X was 5 or greater, it enters with twice that many counters instead.
When bringer of Green Zenith's Twilight dies, shuffle it into its owner's library.
Near Mint - $39,600
Lightly Played - $31,700
Moderately Played - $27,800
Heavily Played - $23,800
Damaged - $19,800
Near Mint Spanish - $39,600
Lightly Played Spanish - $31,700
Moderately Played Spanish - $27,800
Heavily Played Spanish - $23,800
Damaged Spanish - $19,800