It was mentioned briefly on page 1 but I think that Porygon2 deserves more consideration in ORAS league:
Porygon2 @ Eviolite
Ability: Download / Trace / Analytic
EVs: 252 HP / 252 Def / 4 SpD
Bold/Relaxed Nature
IVs: 0 Atk
- Ice Beam
- Thunderbolt / Tri Attack
- Recover
- Thunder Wave
The fact is that MegaMence is a threat and every team needs a check/counter like it or not. Porygon2 fits the bill (geddit because it's a duck) pretty well. It looks like I went crazy on the slashes with the abilities but every single one has it's own ups and downs and after many chats on showdown I believe that any of them can be used. It just depends on the rest of your team and what else other than Mence needs to be checked/countered. And hey, look at it taking a hit!
252+ SpA Aerilate Mega Salamence Hyper Voice vs. 252 HP / 4 SpD Eviolite Porygon2: 72-85 (37.5 - 44.2%) -- guaranteed 3HKO
252+ SpA Mega Salamence Draco Meteor vs. 252 HP / 4 SpD Eviolite Porygon2: 81-96 (42.1 - 50%) -- 0.4% chance to 2HKO
After the stat drop on Draco Meteor that's a 3HKO tops. MegaMence has no way to 2HKO Porygon2.
Download: MegaMence gets a defence boost to 95/130/90 which is just nice for Porygon2 to switch in and get a SpA boost. This boost is critical to a guaranteed OHKO back:
0 SpA Porygon2 Ice Beam vs. 252 HP / 0 SpD Mega Salamence: 156-188 (77.2 - 93%) -- guaranteed 2HKO
+1 0 SpA Porygon2 Ice Beam vs. 252 HP / 0 SpD Mega Salamence: 232-276 (114.8 - 136.6%) -- guaranteed OHKO
The downside is that regular Mence has balanced 95/80/80 base defences. If Mence has a 4EV investment to SpD, Porygon2 will mess up the download on the switch, effectively giving the opponent a little more free room to change strategy. Although depending on the circumstances, this difference may be minimal.
Trace: Trace isn't particularly advantageous for Porgyon2 in terms of defeating Mence, but has the wider benefits of being able to switch out of Shadow Tag users such as Mega Gengar. Like the first calc I did for non-Download Ice Beam, it will not be able to OHKO MegaMence and Aerialate isn't all that amazing (even Aerialate Tri Attack doesn't sound particularly useful unless someone can show me a good use for it). But in terms of taking on other threats it can be considered.
Analytic: And more specifically, -Spe Porygon from a Relaxed Nature. There are a few things that Bold Porgyon2 could speed tie with such as Jellicent, but these are decent trades off for having that great +30%-power-to-all-moves Analytic boost. Namely, the guaranteed OHKO on to MegaMence:
0 SpA Analytic Porygon2 Ice Beam vs. 252 HP / 0 SpD Mega Salamence: 204-240 (100.9 - 118.8%) -- guaranteed OHKO
This thing hurts.
So yeah those are my thoughts regarding Porgyon2 at the moment and I'm still deciding which ability to use. I'm currently breeding non-HA (Analytic) Porgyons so if anyone wants a 5IV one then feel free to PM me since I have a box full! Meanwhile I will consider if I should try to get HA and what else there is which can take on the giant beast that is MegaKhan 2.0