I was guessing the Doctor is actually a fairytale character of some sort as well.
Henry earlier in the episode asked who Lucy would say she was and I felt like that was a clue/hint. Doctor whale was Dr. Frankenstein.
Maybe she is the Bride Of Frakenstein. Fitting given resurrection was kind of the theme going on here. Maybe they need her hair for some kind of ritual. The hair of someone who was dead but lives again might be useful.
Also yeah that’s totes a woman’s arm.
"I could have the giant duck as my steed!" --Daniel Radcliffe
Keeper Of Tamara's Taser , Jafar's Staff, Kitsis’s Glasses , Ariel’s Tail, Dopey's Hat , Peter Pan’s Shadow, Outfit, & Pied Cloak,Red Queen's Castle, White Rabbit's Power To World Hop, Zelena's BroomStick, & ALL MAGIC