Been using this Heracross for quite a few battles, and unprepared teams can be taken down by this. I usually end up losing due to random crits though, so it's not as effective as I could hope it to be.
Status: Complete.
http://www.smogon.com/dp/pokemon/heracross
[SET]
name: Substitute + 3 Attacks
move 1: Substitute
move 2: Close Combat
move 3: Megahorn
move 4: Stone Edge / Night Slash
item: Leftovers
nature: Jolly
evs: 16 HP / 252 Atk / 240 Spe
[SET COMMENTS]
<p>Heracross's other sets require prediction in order to be most effective. However, with Substitute, Heracross does not need to predict as much in order to deal large amounts of damage. Substitute can also block your opponent's attacks and status moves.</p>
<p>Substitute eases prediction as it allows Heracross to scout out the opponent's move or switch-in. Close Combat and Megahorn provide dual 120 base power STABs for Heracross to work with. Low Kick may be used over Close Combat if you do not appreciate the defense drops. However, the power drop against lighter enemies is not appreciated. Heracross will most likely be behind a Substitute anyway, preventing the opponent from hitting it after Heracross has its defenses lowered. Focus Punch is not recommended as Heracross still needs to be able to attack with a Fighting-type move when not behind a Substitute. The final slot improves Heracross' coverage. Stone Edge handles Flying-type Pokemon such as Salamence and Gyarados and keeps them from setting up easily, while Night Slash is your best choice for hitting Rotom-A and Dusknoir.</p>
<p>Either ability works fine here. Guts allows Heracross to freely switch into status moves. Swarm boosts Megahorn's power when Heracross is low on HP. The given HP EVs allow Heracross to attain a Leftovers number plus one, allowing it to use Substitute five times when at full health. 252 Attack EVs let Heracross deal maximum damage, while 240 Speed EVs along with a Jolly nature allow Heracross to get the jump on positive Speed-natured Heatran, positive Speed-natured Gyarados and neutral Speed-natured Rotom-A.</p>
<p>Since this set concentrates on getting up a Substitute and immediately dealing damage, Heracross prefers Dual Screen support in order to soften attacks. It also benefits from paralysis support since Heracross' Speed is only decent. Cresselia, Uxie, Jirachi, and Bronzong all provide Reflect and Light Screen, along with another useful move. Cresselia's Lunar Dance heals Heracross so it can set up more Substitutes. Uxie has Memento, forcing the opponent to switch to remove the stat drops, allowing Heracross to set up a Substitute. Jirachi can pass Wishes to Heracross, while Bronzong can Explode to remove threats from the field and get Heracross in easily. The first three Pokemon also can use Thunder Wave. Getting rid of sturdy physical walls that have recovery such as Gliscor, Skarmory, and Hippowdon can be accommodating for Heracross. Vaporeon, Suicune, and Starmie can handle them with their STAB attacks, and their Water-typing allows them to resist Heracross's Fire-type weakness. Vaporeon can also pass Wish support to Heracross in order to let it set up more Substitutes, while Starmie can Rapid Spin away entry hazards.</p>
<p>Depending on Heracross' last moveslot, it has problems with either bulky Ghost-type Pokemon or Flying-type Pokemon. If Heracross carries Stone Edge, Rotom-A and Dusknoir can wall Heracross due to their large defensive stats. Tyranitar and Scizor can be used for their powerful Pursuits to trap the former two, but they have to watch out for Will-O-Wisp. Tyranitar resists all of Heracross' weaknesses, while Scizor can use U-turn to easily get Heracross in. If Heracross is using Night Slash, Flying-type Pokemon will be a burden. Vaporeon can easily handle Gyarados, while Suicune can deal with both Gyarados and Salamence if it is at high health and has the appropriate move to take care of them. Scizor can revenge kill Salamence should it set up a Dragon Dance.</p>
Status: Complete.

http://www.smogon.com/dp/pokemon/heracross
[SET]
name: Substitute + 3 Attacks
move 1: Substitute
move 2: Close Combat
move 3: Megahorn
move 4: Stone Edge / Night Slash
item: Leftovers
nature: Jolly
evs: 16 HP / 252 Atk / 240 Spe
[SET COMMENTS]
<p>Heracross's other sets require prediction in order to be most effective. However, with Substitute, Heracross does not need to predict as much in order to deal large amounts of damage. Substitute can also block your opponent's attacks and status moves.</p>
<p>Substitute eases prediction as it allows Heracross to scout out the opponent's move or switch-in. Close Combat and Megahorn provide dual 120 base power STABs for Heracross to work with. Low Kick may be used over Close Combat if you do not appreciate the defense drops. However, the power drop against lighter enemies is not appreciated. Heracross will most likely be behind a Substitute anyway, preventing the opponent from hitting it after Heracross has its defenses lowered. Focus Punch is not recommended as Heracross still needs to be able to attack with a Fighting-type move when not behind a Substitute. The final slot improves Heracross' coverage. Stone Edge handles Flying-type Pokemon such as Salamence and Gyarados and keeps them from setting up easily, while Night Slash is your best choice for hitting Rotom-A and Dusknoir.</p>
<p>Either ability works fine here. Guts allows Heracross to freely switch into status moves. Swarm boosts Megahorn's power when Heracross is low on HP. The given HP EVs allow Heracross to attain a Leftovers number plus one, allowing it to use Substitute five times when at full health. 252 Attack EVs let Heracross deal maximum damage, while 240 Speed EVs along with a Jolly nature allow Heracross to get the jump on positive Speed-natured Heatran, positive Speed-natured Gyarados and neutral Speed-natured Rotom-A.</p>
<p>Since this set concentrates on getting up a Substitute and immediately dealing damage, Heracross prefers Dual Screen support in order to soften attacks. It also benefits from paralysis support since Heracross' Speed is only decent. Cresselia, Uxie, Jirachi, and Bronzong all provide Reflect and Light Screen, along with another useful move. Cresselia's Lunar Dance heals Heracross so it can set up more Substitutes. Uxie has Memento, forcing the opponent to switch to remove the stat drops, allowing Heracross to set up a Substitute. Jirachi can pass Wishes to Heracross, while Bronzong can Explode to remove threats from the field and get Heracross in easily. The first three Pokemon also can use Thunder Wave. Getting rid of sturdy physical walls that have recovery such as Gliscor, Skarmory, and Hippowdon can be accommodating for Heracross. Vaporeon, Suicune, and Starmie can handle them with their STAB attacks, and their Water-typing allows them to resist Heracross's Fire-type weakness. Vaporeon can also pass Wish support to Heracross in order to let it set up more Substitutes, while Starmie can Rapid Spin away entry hazards.</p>
<p>Depending on Heracross' last moveslot, it has problems with either bulky Ghost-type Pokemon or Flying-type Pokemon. If Heracross carries Stone Edge, Rotom-A and Dusknoir can wall Heracross due to their large defensive stats. Tyranitar and Scizor can be used for their powerful Pursuits to trap the former two, but they have to watch out for Will-O-Wisp. Tyranitar resists all of Heracross' weaknesses, while Scizor can use U-turn to easily get Heracross in. If Heracross is using Night Slash, Flying-type Pokemon will be a burden. Vaporeon can easily handle Gyarados, while Suicune can deal with both Gyarados and Salamence if it is at high health and has the appropriate move to take care of them. Scizor can revenge kill Salamence should it set up a Dragon Dance.</p>