Mega Altaria as a
check.
Altaria @ Altarianite
Ability: Natural Cure
EVs: 252 HP / 136 Def / 92 SpD / 28 Spe
Impish Nature
- Body Slam
- Dragon Dance
- Heal Bell / Refresh
- Roost
Altaria is a great switchin to just about all Latios variants, and while Specs is its only set that allows it to 2HKO Altaria (with Psychic that is, since Psyshock only has a chance to 2HKO after rocks
and you should be running Psychic anyway), Altaria can safely switch into all of its coverage options as well as Trick, meaning it can force mindgames for the Lati player since they can only click Psychic to avoid giving the Altaria player a free switch. And of course, in return, Altaria can either start setting up if its checks are thoroughly weakened or it can throw out a Body Slam to OHKO Lati or potentially cripple one of its teammates in the process.
252 SpA Choice Specs Latios Psychic vs. 252 HP / 92 SpD Mega Altaria: 195-229 (55 - 64.6%) -- guaranteed 2HKO after Stealth Rock
252 SpA Choice Specs Latios Surf vs. 252 HP / 92 SpD Mega Altaria: 65-76 (18.3 - 21.4%) -- guaranteed 5HKO after Stealth Rock
0 Atk Pixilate Mega Altaria Body Slam vs. 0 HP / 4 Def Latios: 312-368 (103.6 - 122.2%) -- guaranteed OHKO