In an enticing Once Upon a Time sneak peek for Sunday’s “The Doctor,” Dr. Whale seeks out Charming (with hilarious results). But what does he want to know?

In the clip, Whale seeks out David, only to get punched in the face for sleeping with Mary Margaret. David knows that it was because of the curse, of course, but we’re sure no one begrudges him a little payback anyway!

It turns out that Whale actually came to David to ask what he knew about the portal to the other side. It seems like the good Doctor is more concerned about whether fairytale land still exists than whether Emma and Mary Margaret is okay… but why?

Considering the terrifying promo released for the episode, it doesn’t seem like a stretch to assume that Whale is Once Upon a Time‘s version of Doctor Frankenstein, and once upon a time (hehe) he scared Regina senseless by re-animating the body of her dead lover Daniel.

In “The Doctor,” Regina will be haunted by a ghost from her past, which may also be Daniel – is Whale causing this? Is there some reason why he really wants to get back to the Enchanted Forest, or perhaps a reason why he doesn’t?

We can’t wait to learn more about this character’s backstory! Once Upon a Time 2×05 “The Doctor” airs this Sunday at 8/7c on ABC, and it seems like the perfect episode to air right before Halloween!

Listen to Hypable’s Once Upon a Time podcast Onceable to learn what the hosts thought about last week’s episode “The Crocodile,” and hear their theories about what’s ahead for our storybook favourites!

And be sure to also visit the Hypable forums, where there’s a lively Once Upon a Time discussion thread in which you can share your theories.