Cela dit, ici, j'aurai tendance à être d'accord avec Lyo. Dans le cas présent, il s'agit d'un effet continu avec une certaine durée. Un tel effet s'arrête au moment précis où sa durée expire.
Citation :
611.2a A continuous effect generated by the resolution of a spell or ability lasts as long as stated by
the spell or ability creating it (such as “until end of turn”). If no duration is stated, it lasts until
the end of the game.
[...]
702.102a Bestow represents two static abilities, one that functions while the card with bestow is on the stack and another that functions both while it’s on stack and while it’s on the battlefield. “Bestow [cost]” means “You may cast this card by paying [cost] rather than its mana cost.” and “If you chose to pay this spell’s bestow cost, it becomes an Aura enchantment and gains enchant creature. These effects last until one of two things happens: this spell has an illegal target as it resolves and or the permanent this spell becomes, becomes unattached.” Paying a card’s bestow cost follows the rules for paying alternative costs in rules 601.2b and 601.2e–g.
Dans le cas de la prêtresse banisseuse, ce qui ramène la créature est un one-shot effect créé juste après le départ de la prêtresse.