Rule 702.103b

As a spell cast bestowed is put onto the stack, it becomes an Aura enchantment and gains enchant creature. It is a bestowed Aura spell, and the permanent it becomes as it resolves will be a bestowed Aura. These effects last until the spell or the permanent it becomes ceases to be bestowed (see rules 702.103e–g). Because the spell is an Aura spell, its controller must choose a legal target for that spell as defined by its enchant creature ability and rule 601.2c. See also rule 303.4.

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