Enchantment creature targeting

[Destore117]

So I was wondering if you could target an enchantment creature that's being used to enchant a creature.
For instance opponent plays {knight of Infamy} enchanted with {nighthowler}
I can't use { {Intrepid Hero} on knight but can I use it on howler?

[Kaleo42]

No, because the {night howler} isn't a creature.  It's just an enchantment.

....for as long as it is enchanting said creature.