I agree it would be super sneaky, but then how would you explain the adult seer? She was burdened by her seeing ability and freely gave the “gift” to Rumple so that she could be free of it. Then she died.
She appeared to die, (doesn’t necessarily mean she did). After showing and telling Rumple the info he needed for the plan for the Curse to move ahead, (Blue was the one who put the idea about a Curse in his head to begin with, right after Bae went down the beanhole, the Seer basically just confirmed it). If it was Blue tricking him and the whole thing was an act, then it makes sense that she’d shapeshift herself into an adult if time had passed since Rumple had seen the Seer as a child.
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