Having talking spokescharacters can get a little weird if the characters are items of the food product you're selling, and using sex to sell candy creeps me out. So when M&Ms manages to make an ad that goes wrong in both of these ways? I'm not a fan.
There are about a million ways this is wrong. Let's enumerate just a few of them:
1. The attempted sexuality of the bare legs and high heels.
2. The purring, bedroom-voice voice-over.
3. The horrible "seductive poses."
4. The wink.
5. The fact that an M&M is eating other M&Ms.
Why, M&Ms? Why do you think it makes sense to sell your product with creepy, utterly repulsive "sexually appealing" candy? Your audience is not made up of M&Ms (even if it were, M&Ms quite clearly lack genitalia, so I fail to see how they would put their desire into action). Your audience is humans, and humans don't want to have sex with M&Ms. Therefore, you do not need your main spokescharacter to be a "sexy" M&M; really, there's no such thing, in spite of how you pretend otherwise.
Now yes, I'm aware of the longstanding rumor (spread by complete idiots) that green M&Ms serve as some sort of aphrodisiac. And I'm also aware that M&Ms started to use the "sexy" female green M&M to play on that (only, what, two decades behind the curve of the urban legend). But if you're going to do that? You use sexy humans and regular green M&Ms. You do not use sexy M&Ms. This would still be terrible - because when I think of sex, I do not think of M&Ms - but at least it doesn't make me think that you think I want to fuck your candy.
The cannibalism subplot of this ad is underrated, by the way. This is the same company that ran a surprisingly sadistic ad ten years ago in which Diedrich Bader mockingly consumes Crispy M&M's entire family while Crispy watches helplessly; now, however, it's apparently okay for new M&M brands to be eaten, even by existing M&M brands. Unless that's really why the other M&Ms are staring at the end of the ad. "I can't believe she ate Jerry in cold blood! I mean, in cold chocolate! Just right down the hatch! Also, do we even have digestive tracts? Where do you think he went?"