Grumpig- Mega
Psychic/
Fairy
Ability: Thick Fat/Own Tempo/Gluttony->
Filter
Stats
HP: 80
Atk: 45
Def: 95 (+30)
SpA: 120 (+30)
SpD: 150 (+40)
Spe: 80
New Ability: +
Heal Bell, Slack Off
Grumpig's psychic power expands so much that it can force the opponent to subconsciously nerf their super-effective attacks. With Blissey being made too passive to consistently function in SV and Glowking not available due to format specifics, Mega Grumpig is able to step up as an easy to fit eater of special hits, especially now that it has
Heal Bell again to pull cleric duties. Newfound Fairy type grants it a more spammable STAB in
Dazzling Gleam while giving it a valuable immunity to the fierce Dracos of Walking Wake, Raging Bolt and Specs Dragapult; Fairy also mitigates otherwise debilitating weaknesses to U-turn and Dark. Max HP alone is enough to survive Booster Energy Sludge Wave from Iron Moth, which you easily OHKO after Rocks, though you also have mind-games versus Moth thanks to pre-Mega Thick Fat.
Slack Off allows Grumpig to heal up versus the special attackers it has to handle, hitting them respectably hard with
Psyshock (particularly nice for the Volcarona matchup) and a great coverage move in
Earth Power, disrupting with
Thunder Wave or
Encore or stalling them out with your own
Calm Mind.
Mega Grumpig naturally pairs well with the plethora of Dark types, sponging Fighting attacks while Dark types handle its Ghost weakness. It also appreciates forming a defensive core Alomomola or Dondozo, who sponge physical and Steel attacks while Grumpig can deal with their biggest Achilles heel by curing status, as well as ensuring Draco spammers can't exploit Dozo's Unaware.
Dachsbun- Mega
Fairy
Ability: Well-Baked Body/Aroma Veil->
Lingering Aroma
Stats
HP: 57
Atk: 115 (+35)
Def: 145 (+30)
SpA: 65 (+15)
SpD: 100 (+20)
Spe: 95
New Moves: +
Follow Me, Wide Guard
Dachsbun lore really fixates on aroma, so the direction was obvious; Bread Dog's aroma is now so strong it overpowers abilities. In Singles, Lingering Aroma and its buffed defenses allow Mega Dachsbun to be an annoying disrupter, nerfing ability-reliant attackers like Kingambit, Chien-Pao, Mega Lokix and the various physical Paradox mons (yes, LA works on Proto and Quark), most notably Great Tusk and Gouging Fire. Bread Dog gets enough Atk that it isn't exclusively reliant on
Body Press for Damage, now able to more effectively use STAB
Play Rough to hit targets like Valiant. The buffed defenses allow
Wish to be sufficient for healing.
Where Mega Dachsbun really shines, however, is VGC, as it can leverage new support options
Follow Me and
Wide Guard to shield its teammates. Follow Me + Lingering Aroma is the main draw as it allows Bread Dog to forcibly remove the ability of any physical attacker while protecting its teammate; it being so potentially potent is why I kept Dachs physical, as letting it ignore burns and Intimidate might be too much. Wide Guard means Dachs has an option versus spread moves like Heat Wave and Discharge. From there, you can boost your ally further with
Helping Hand, drop attacking stats with
Charm or
Snarl, or spec into Play Rough as a STAB option, all while using Body Press for consistent damage. You can even delay the Mega and use Follow Me to screw with Chi-Yu before unleashing +2 Body Press.
Arboliva- Mega
Grass/Normal
Ability: Seed Sower/Harvest->
Sapping Sludge: User's targeting Grass type moves lower the target's Speed by one stage.
Stats
HP: 78
Atk: 99 (+30)
Def: 95 (+5)
SpA: 145 (+20)
SpD: 129 (+20)
Spe: 64 (+25)
The production of olive oil leaves behind a biohazardous substance called "pomace" which is toxic to many plants; Mega Arboliva secretes a similar substance onto its enemies which impedes their movement, allowing Arboliva and its allies to get the jump on them more easily. Mega Arboliva's ability lets it take a proactive role in speed control, pairing well with its natural tools in
Giga Drain,
Strength Sap or occasional
Leech Seed; however, you also have the funny option of multi-stage drop
Bullet Seed (though you do need 3 hits to outpace stuff like Chien-Pao). In Singles, Arboliva mainly targets faster offensive threats, using its ability to rob them of valuable turns. Once the target is slowed down, you get let loose your strong special attacks between
Earth Power,
Dazzling Gleam or STAB
Hyper Voice, or swap to a teammate that can outpace what would otherwise be a scary offensive threat, with pre-Mega Seed Sower giving your first swap a little more leeway.
The ability to drop Speed is particularly useful in Doubles, where speed control is especially nice, especially since you have two different multi-hit Grass moves in
Razor Leaf and
Petal Blizzard; Razor Leaf only targets opponents, but the fact Petal Blizzard hits your ally can be used to proc Defiant/Competitive shenanigans. You can also leverage PB to improve a teammate's speed under Trick Room, especially since you can easily heal your allies up with
Pollen Puff. Mega Arboliva pairs quite solidly with Kingambit, which appreciates Arboliva's Grass moves weakening Water and Ground types while exploiting potential speed drops thanks to Defiant and its natural Grass resist.