Waves of Change
Mega Heracross is one of the most powerful wallbreakers in the tier, being able to dismantle defensive teams with Swords Dance along with its high Attack stat. Having a unique defensive typing along with respectable bulk allows Mega Heracross to check many top-tier offensive threats such as Swords Dance Tapu Bulu and Zygarde as well as act as a solid Dark-type check. On the other hand, Mega Heracross's typing also leaves it weak to common types in Fairy, Flying, and Fire, and both of its STAB moves share common resistances, oftentimes being redundant in terms of coverage. In addition to its common weaknesses, Mega Heracross's poor Speed tier makes it easy to revenge kill for Pokemon like Tapu Lele, Mega Alakazam, and Mega Pinsir. Due to its tendency to fall against faster offensive threats, Mega Heracross tends to struggle against highly offensive teams.
name: Swords Dance
move 1: Swords Dance
move 2: Close Combat
move 3: Rock Blast
move 4: Pin Missile / Substitute / Bullet Seed
nature: Adamant / Jolly
evs: 252 Atk / 4 SpD / 252 Spe
Swords Dance allows Mega Heracross to boost its already high Attack stat to astronomical levels and break through bulkier teams with ease, allowing it to take down Toxapex and Clefable much more easily. Close Combat is Mega Heracross's main STAB move and can even 2HKO many bulky neutral targets, such as Zygarde and Celesteela. Rock Blast is an excellent coverage move that becomes an effective 125-Base Power Rock-type attack with Skill Link that allows Mega Heracross to take on Pokemon that resist its STAB attacks, such as Toxapex, Clefable, and Tornadus-T. Finally, the last slot is a toss-up based on a combination of team structure and personal preference. The most common option is Pin Missile for its ability to pressure bulky Psychic-types such as Reuniclus and Mega Latias. Alternatively, Substitute can be used to allow Mega Heracross to more freely set up against Pokemon like Toxapex and Amoonguss as well as easing prediction against more offensive teams. Mega Heracross can also opt to go for Bullet Seed when paired with Tapu Bulu to have a pseudo-STAB move that can 2HKO many would-be checks, such as Clefable and defensive Flyinium Z Landorus-T.
252 Attack and Speed EVs with an Adamant nature maximize Heracross's attacking power and Speed, making it an effective wallbreaker. However, a Jolly nature can be used to outspeed Timid Heatran and Jolly Mamoswine prior to Mega Evolution as well as Modest Heatran and Adamant Mamoswine after. Moxie allows Mega Heracross to gain boosts upon KOing Pokemon such as Heatran and Tyranitar prior to Mega Evolution so that it can garner some boosts early on without having to set up. On the other hand, Guts can be used over Moxie to allow Heracross to fare better against bulkier teams that rely on status conditions, such as burn, to cripple wallbreakers.
Pivot Mega Heracross into Pokemon that don't pose a threat to it, such as Zygarde, Tapu Bulu, and Chansey, early-game so that it can break the opposing team. If running Jolly Heracross, consider not Mega Evolving it prior to KOing Pokemon base-forme Heracross outspeeds that Mega Heracross cannot such as Heatran and Mamoswine. Attempt to chip checks such as Clefable and Toxapex into range of Rock Blast by pressuring them with Pokemon that share them as mutual checks such as Zygarde and Greninja respectively. Avoid using Swords Dance against slower Pokemon that threaten to KO Mega Heracross, such as Z-Move Reuniclus and Magearna, early on, seeing as Mega Heracross's absurd Attack stat means that it will likely put a dent into whatever switches into it anyway. However, don't be afraid to use Swords Dance when facing bulkier teams, as Mega Heracross can completely decimate these teams after a boost.
Seeing that Mega Heracross is a wallbreaker, it appreciates pivots such as Choice Scarf Landorus-T and Assault Vest Magearna that can bring it in and allow it to break down the opposing team without taking unnecessary damage. Additionally, entry hazard support from Pokemon such as Greninja and Ferrothorn is very useful due to the sheer number of switches that Mega Heracross forces, resulting in damage building up on opposing teams if entry hazards are up. Clefable in particular is a useful teammate because it can provide Wish support to Mega Heracross, allowing it to consistently check Pokemon such as Tapu Bulu and Zygarde while also functioning as a durable wallbreaker that can rip through an opposing team on top of being able to wear down the opposing team with Stealth Rock. Late-game cleaners such as Shift Gear Magearna and Dragon Dance Zygarde appreciate Mega Heracross's ability to punch holes in teams and make it much easier to set up and sweep late-game. If Mega Heracross is using Bullet Seed, Tapu Bulu is an important teammate due to Grassy Terrain giving Bullet Seed a sizable boost, allowing it to 2HKO Clefable and hit a slew of other targets. Should Mega Heracross choose to forego Pin Missile in favor of other coverage or Substitute, Pursuit trapping from the likes of Weavile or Tyranitar is appreciated, as they can KO threats such as Mega Latios that would otherwise wall it. Mega Heracross's inability to check Heatran from the Mega Slot position oftentimes leaves its teams liable to Heatran, so teammates such as Gliscor that can check Heatran are invaluable assets when constructing a Mega Heracross team. Finally, Pokemon that resist Flying such as Tapu Koko and Heatran function well alongside Mega Heracross to cover up for its defensive weaknesses. Tapu Koko in particular is an effective teammate because it also functions as a pivot that allows Mega Heracross to break opposing teams.
Mega Heracross can also utilize an all-out attacking set with Earthquake over Swords Dance to threaten bulkier teams without having to set up, but it fails to break through many of its normal checks, mainly Clefable, and it's very reliant on prediction to be successful. Rest can be used as another mode of breaking through bulkier teams, making Mega Heracross much less crippled by status, but this set struggles in every matchup that it isn't facing full stall.
Checks and Counters
**Flying-types**: Flying-type Pokemon such as Tornadus-T and Mega Pinsir resist Mega Heracross's STAB moves and threaten to OHKO it with super effective STAB attacks, but they have to be wary of switching into a potential Rock Blast. Supersonic Skystrike Landorus-T is especially troublesome due to its neutrality to Rock Blast.
**Psychic-type Attacks**: Offensive Psychic-types such as Mega Latios, Tapu Lele, and Mega Alakazam all switch into Mega Heracross's Close Combat with varying degrees of ease and threaten it out with super effective STAB attacks, but they all have to be careful switching into Mega Heracross, as they must avoid Pin Missile. Additionally, Pokemon that carry Psychic-type attacks, such as Psychium Z Greninja, can catch Mega Heracross off guard and OHKO it.
**Fire-types**: Fire-type Pokemon such as Heatran and Volcarona threaten to OHKO Mega Heracross with their STAB attacks as well, but they oftentimes cannot pivot directly into Mega Heracross due to being OHKOed by Close Combat and Rock Blast respectively.
**Fairy-types**: Offensive Fairy-types such as Tapu Lele can threaten to OHKO Mega Heracross. However, Unaware Clefable is arguably the best Mega Heracross counter in the tier, being able to switch into it and avoid being 2HKOed by any attack, though it has to be wary of being whittled down by entry hazards and the rare Grassy Terrain-boosted Bullet Seed. Magic Guard Clefable is similarly annoying, being difficult to whittle down and taking any attack from full at +2 besides Bullet Seed in Grassy Terrain.