What if Kyurem learned Frost Breath?
Just a recap for those who don't really know what Frost Breath does, it's a Special 40BP/90ACC Ice move that has guaranteed crit. Now, just putting it out there, it's pretty weak hitting only 80BP after the crit is applied (Ice Beam sits at 95BP). But the crit is something that could actually be utilized. It brings up a totally different question which many players overlook due to the "hax" nature of critting. If crits were "reliable", could they be utilized effectively?
Now, crits are pretty nifty in that they bypass any def boosts from your opponent as well as bypass any atk drops from yourself. What I'm hinting here is that Frost Breath can effectively bypass they SpA drop that Draco Meteor gives, meaning you're not handicapped after using Draco Meteor. It's also a way to hit through CM users, but those scenarios are rare compared to the interaction you'll have with Meteor. There is a problem with Frost Breath though being weaker than Ice Beam before any drops, also if your opponent happens to have Battle Armor/Shell Armor as an ability you're stuck unable to crit. Still, I would say this is definitely an interesting concept. It's been in the games since forever but always as a form of hax. With this, we can actually make crits "work".
Also, seeing that Frost Breath is a rare move, your opponent probably won't know that it guarantees crit. It might be funny seeing them rage at you screaming "crit hax" and such :p
I have another concept using the physical variant of Frost Breath, but I'll save that for later.