This COULD be one of the legendary trios. Pokexperto posted a silhouette this morning and now we have these screenshots. No proof that these are legit yet, I’ll send a quick email to Melkor 😉
UPD: (The following is an ozy takeover) These Pokemon are the REAL legendary trio but, they are not real screenshots. So, they will look very similar to this, but the sprites you see in the game might look slightly different.
ps- Thanks Bayleef for the tip!