Enchantment, 1U (2) When an opponent casts a spell, if Veiled Apparition is an enchantment, Veiled Apparition becomes a 3/3 Illusion creature with flying. That creature has "At the beginning of your upkeep, sacrifice Veiled Apparition unless you pay {1}{U}."1
Illus. Andrew Robinson
10/4/2004: You choose whether to pay or not on resolution. If not, then you sacrifice the creature. You can choose to not pay if you do not control the creature on resolution.
10/4/2004: When it turns into a creature, it is no longer an enchantment.
10/4/2004: It changes into a creature even if the spell is countered.
10/4/2004: It triggers when the spell is cast, which means it becomes a creature before that spell resolves.
8/1/2008: A noncreature permanent that turns into a creature is subject to the "summoning sickness" rule: It can only attack, and its {T} abilities can only be activated, if its controller has continuously controlled that permanent since the beginning of his or her most recent turn.
Urza's Saga
(Uncommon)