In a desperate attempt to save Star, Marco opted to utilize her wand and in his hands, it morphed into a form more suitable for him. But why wings? Bat/demon wings to be exact? That basically screams evil.
This has gotten me very concerned. Remember the time when he got a monster arm and we were never actually sure if it’s a hundred percent gone?
And all these theories popped up, saying that Marco has a monster part in him and will eventually play a part in Mewni’s downfall as Toffee’s minion and leverage against Star. Thank the heavens it didn’t happen BUTsome details may actually be one on point like how Marco will be a very significant character in the show’s greatest conflict sometime in the near future. He may be a total cinnamon roll, but we can’t be blind to things that happen to him, like:
In “Page Turner”, Star was able to resist the forbidden chapter’s temptation of learning dark magic, but Marco hadn’t and he ended up suspended in a whirlpool of evil energy, full-blown crazy.
HE DESIRED DARK MAGIC.
Marco has an evil side in him and he’s not, including everyone around him, picking up on it. (I really hope I’m wrong.)
And we know violet is Eclipsa’s color scheme, right? Her pajamas, dress, the glowing clubs on her cheeks, her tapestry-
AND THE CRYSTAL ON MARCO’S WAND
Somehow, Marco reading Eclipsa’s chapter connected him to her, or maybe, they’re connected by a bigger reason that will soon be revealed because Marco dragged into Mewni’s mess and more specifically, Star’s life, is definitely no coincidence (almost like it’s predestined, I mean why did Star end up staying in his house in the first place, right?).