I've been using this Pokemon today a lot and I'm seriously impressed. Every time he switches in, he's made a big difference to the game.
I've been using this set:
Bisharp @ Life Orb
Ability: Defiant
EVs: 252 Atk / 252 Spe / 4 HP
Adamant Nature
- Sucker Punch
- Substitute
- Swords Dance
- Iron Head
While it has obvious longevity issues, its killing potential with some prior damage on the enemy team is highly reliable and surprises me every time. The combo of sucker punch and substitute is obvious- either they attack you and get smacked first with the hardest hitting priority STAB life orb boosted (and possibly +1 or +2 boosted) attack in the game, or they cast a non-attacking move/ switch out, and risk you putting up a sub. To break the sub and kill you afterwards, they then have to hit you twice, which means a definite two sucker punches in the face beforehand. So I would argue that whilst you are putting your life on a timer with this set, you become so much trickier to take down without the opponent losing a huge chunk of their team and are trading off several of Bisharp's shortcomings, which include his low defenses, low speed when using Iron Head, and fear of not being able to ohko an opponent, as well as issues with status moves.
Sucker Punch has a lot of its problems solved by Substitute, so its the only dark type move on the set. Iron Head is the obligatory secondary STAB and obviously hits fairies that resist dark type moves hard.
Bisharp forces so many switches that sub seems perfect for him. Even though it blocks status drops, no-one will be intentionally using their defog on a Bisharp anyway, and defiant still helps you on that first turn you switch in. I think more people need to try it out, I don't see any Bisharps using sub even though its so effective on him- I'm pretty sure sub was common on him last gen too so I don't really know what happened.