Arcanum Naiad

Bestow {1}{u} (If you cast this card for its bestow cost,
it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Ward {3}
If Arcanum Naiad is an Aura, it has "Enchanted creature has ward {3}" and aura swap {2}{u}. Otherwise, Auras attached to it have aura swap {2}{u}. ({2}{u}: Exchange this Aura with an Aura
card in your hand.)