Opal Archangel
Enchantment
When an opponent casts a creature spell, if this permanent is an enchantment, it becomes a 5/5 Angel creature with flying and vigilance.
Jeff Miracola
Urza's Saga (USG)
• #23Rulings
A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.
(wotc • 2008-08-01)
A "creature spell" is any spell with the type Creature, even if it has other types such as Artifact or Enchantment. Older cards of type Summon are also Creature spells.
(wotc • 2008-04-01)
It triggers when the spell is cast, which means it becomes a creature before that spell resolves.
(wotc • 2004-10-04)
It changes into a creature even if the spell is countered.
(wotc • 2004-10-04)
When it turns into a creature, it is no longer an enchantment.
(wotc • 2004-10-04)
Rulings
A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.
(wotc • 2008-08-01)
A "creature spell" is any spell with the type Creature, even if it has other types such as Artifact or Enchantment. Older cards of type Summon are also Creature spells.
(wotc • 2008-04-01)
It triggers when the spell is cast, which means it becomes a creature before that spell resolves.
(wotc • 2004-10-04)
It changes into a creature even if the spell is countered.
(wotc • 2004-10-04)
When it turns into a creature, it is no longer an enchantment.
(wotc • 2004-10-04)