Turbo from Ralph is good and unexpected villian too and with good subtle hints as well.
Thisthisthisthisthis
You can’t just make a character start being evil with no explanation or foreshadowing or any character hints whatsoever. It makes the viewer feel cheated.
I feel like this is… The first time I saw Frozen, I had no idea Hans was the villain. I came in unspoiled. During “Love is an Open Door” I started shaking, because the way he moved and mirrored Anna, the way he waited for her cues before responding to her reminded me so much of what my abuser did to lure in new victims. Obviously this was a bad way to react to a potential Disney love interest, and I almost walked out. When he turned out to be the villain I was so relieved. The movie makers were foreshadowing, but I think they 1) didn’t want Anna to look too much like an idiot for falling for him, and 2) didn’t realize most of the adults in the audience can’t spot a cold read.
I actually suspect that much of this is do to the fact that originally Elsa (the Snow Queen) was supposed to be the villain, but they changed their minds part way through the creating process. They changed their minds because some (one?) of the songs struck them as better for a different context, and they did a pretty damn good job of showing that sort of emotional manipulation, but because they wouldn’t let there be a complete overhaul like there should have been you can still see huge sections of the original plot showing through, which is why we have the disconnect and why it still seems like him being the villain comes out of the blue.
^Didn’t the same thing happen with The Magic Flute (Mozart’s librettist changed his mind halfway through about which character should be the villain)?