This recent commercial is definitely more vague then any of the others but my thought was QS/whatever other force is in Westview as the shark and wanda as the kid
On the basis that each commercial have simultaneously been references to a part of Wanda's life and a reference to events happening in the show, I think the commercial is both a reference to her prison time where she was isolated and not being able to use her powers in Civil War, and I think it's message in relation to the show is very clear.
Wanda is the boy, she's so filled with grief (hungry) and feels isolated (island), because the love of her life (the fish bones) is dead (it's dead).
Agnes (the crab) summons Mephisto/whoever the heck (raises its arms).
Mephisto says, "Sad? I remember being sad, I used to be like that all the time".
Wanda asks "What did you do?"
Mephisto says "I fed off your magic, now I have time to finish what I started."
Wanda wants some so she can fix her grief (a deal). Mephisto says sure. This leads to Westview.
Wanda is trying to use her magic to get past the grief and isolation, but ultimately after 9 episodes (9 days pass in the commercial if you watch the sun/moon), she fails to truly fix the situation and "dies", while Mephisto is still looming around (the shark is still there around the island waiting for the end of the commercial) the whole time.