The core in general have problems psychic types and ice types but we will go to the partners later. For a really annoying threat to this core now:
Sneasel @ Life Orb
Ability: Inner Focus
Shiny: Yes
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
IVs: 29 HP
- Knock Off
- Low Kick / Iron Tail
- Pursuit
- Icicle Crash
This core has huge troubles against ice types that are above the 105 speed tier... so just this one even though manectric would take a good chunk from mega glalie ice shard, it will kill back with flamethrower. Anyways, to the threat in question, sneasel eats flygon alive with a safe switch-in, has a chance to downright kill manectric with knock off after just a bit of prior damage (in fact, it has a chance to kill with no prior damage but after rocks or life orb recoil is basically dead) and while sawk would check it, it cant switch into it at all fearing to lose its band and the combination of knock off + icicle crash easily KO. Lesson of the day: pack ice resists.
252 Atk Life Orb Sneasel Knock Off (97.5 BP) vs. 0 HP / 4 Def Sawk: 104-123 (35.7 - 42.2%) -- guaranteed 3HKO
252 Atk Life Orb Sneasel Icicle Crash vs. 0 HP / 4 Def Sawk: 185-218 (63.5 - 74.9%) -- guaranteed 2HKO