When an opponent casts an instant spell, if this permanent is an enchantment, it becomes a 4/4 Ape creature.
The ability triggers when the spell is cast, so it becomes a creature before the spell resolves.
A noncreature permanent that turns into a creature can attack, and its 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.
When it turns into a creature, it is no longer an enchantment.
It changes into a creature even if the spell is countered.
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.