Celestial Archon

Bestow is an alternative cost to cast the spell with bestow. It can't be combined with other alternative costs, such as casting a spell "without paying its mana cost."

If a permanent with bestow enters the battlefield by any method other than being cast, it will be an enchantment creature. You can't choose to pay the bestow cost and have it become an Aura.

Unlike other Aura spells, an Aura spell with bestow still resolves if its target is illegal. Instead of entering the battlefield as an Aura, the effect making it an Aura spell ends, it loses enchant creature, and it resolves and enters the battlefield as an enchantment creature.