That Gengar set looks pretty cool, might have to try out a similar set on my hyper offence team. Speaking of here's an under rated mon I've been using as a backup sweeper:
Sharpedo @ Life Orb
speed boost
hasty nature
252atk/4apatk/252spd (You can move these around however you Wish, max speed isn't a requirement because of speed boost so you could run an offence boosting nature and/or taking evs from atk and speed to put into special attack to hit specific threats.)
- water fall
- crunch
- ice beam
- aqua jet
As implied by the bold aqua jet is the crux of this set. It may seem absolutely stupid to run speed boost and priority, your ability gives you all the speed you need right? Wrong. The crazy speed of the metagame means priority is often used as a revenge killing tool. Ice shard is an emergency dragon stopper, scizor puts big dents in opponents mid sweep and priority in general has made set up sweeping slightly less viable.
A combination of aqua jet and speed boost means you're not vulnerable to being revenged by priority users (except e-speed and healthy technilooms, the latter is a big except though considering it resists sr). It may seem suicidal not to have protect to get that first speed boost but it plays similar to standard sharpedo. You aren't coming in on anything other than psychic attacks and your own team's slow volt-turn so you don't take damage on the switch, sometimes with your opponent taking extra damage. Instead of protecting for your first move which might be exploited with a free switch into a faster scarfer you can secure a free kill with your priority and get your boost.
There are two things sharpedo downright loves; rain and hazards. Deoxys is an obvious choice for crazy hazard stacking. Politoed seems like the other obvious pokemon for the job but weather wars kill your momentum and sharpedo excels at hyper offence, he doesn't need the rain for prolonged amounts of time and it's more important for buffing aqua jet early sweep than the full power waterfall through out the entire end game. Sharpedo benefits much more from rain dance users with synergy and an offensive presence than he does from politoed and the annoying weather war it brings. Tornadus - I is decent, resisting loom's STABs, having u-turn, a hurricane more powerful than tornadus - T and priority rain dance and taunt, as well as a strong super power to crush ferrothorn who can stall you out. Other than that slower u-turn and volt switch users are Sharpedo's bffs for getting him in unscathed and doing half the job for him.
I use him for my HO team and he does both a great job sweeping late game and revenging. An important warning though, Sharpedo is FRAIL. He has like 60/40/40 defences and can be 2hkoed by even resisted STABs from weaker support pokemon. With hazards and LO he needs to be healthy to do his job. Rapid spin support is nice but not necessary as even with 3 layers of spikes and rocks up he has seven turns of LO recoil left. He's weak to both halves of volt-turn and Mach punch and the only notable opportunity to switch in is on an immune psychic attack. Unless you're absolutely adamant your opponent will use a psychic attack don't switch in with sharpedo, ever.
Sharpedo @ Life Orb
speed boost
hasty nature
252atk/4apatk/252spd (You can move these around however you Wish, max speed isn't a requirement because of speed boost so you could run an offence boosting nature and/or taking evs from atk and speed to put into special attack to hit specific threats.)
- water fall
- crunch
- ice beam
- aqua jet
As implied by the bold aqua jet is the crux of this set. It may seem absolutely stupid to run speed boost and priority, your ability gives you all the speed you need right? Wrong. The crazy speed of the metagame means priority is often used as a revenge killing tool. Ice shard is an emergency dragon stopper, scizor puts big dents in opponents mid sweep and priority in general has made set up sweeping slightly less viable.
A combination of aqua jet and speed boost means you're not vulnerable to being revenged by priority users (except e-speed and healthy technilooms, the latter is a big except though considering it resists sr). It may seem suicidal not to have protect to get that first speed boost but it plays similar to standard sharpedo. You aren't coming in on anything other than psychic attacks and your own team's slow volt-turn so you don't take damage on the switch, sometimes with your opponent taking extra damage. Instead of protecting for your first move which might be exploited with a free switch into a faster scarfer you can secure a free kill with your priority and get your boost.
There are two things sharpedo downright loves; rain and hazards. Deoxys is an obvious choice for crazy hazard stacking. Politoed seems like the other obvious pokemon for the job but weather wars kill your momentum and sharpedo excels at hyper offence, he doesn't need the rain for prolonged amounts of time and it's more important for buffing aqua jet early sweep than the full power waterfall through out the entire end game. Sharpedo benefits much more from rain dance users with synergy and an offensive presence than he does from politoed and the annoying weather war it brings. Tornadus - I is decent, resisting loom's STABs, having u-turn, a hurricane more powerful than tornadus - T and priority rain dance and taunt, as well as a strong super power to crush ferrothorn who can stall you out. Other than that slower u-turn and volt switch users are Sharpedo's bffs for getting him in unscathed and doing half the job for him.
I use him for my HO team and he does both a great job sweeping late game and revenging. An important warning though, Sharpedo is FRAIL. He has like 60/40/40 defences and can be 2hkoed by even resisted STABs from weaker support pokemon. With hazards and LO he needs to be healthy to do his job. Rapid spin support is nice but not necessary as even with 3 layers of spikes and rocks up he has seven turns of LO recoil left. He's weak to both halves of volt-turn and Mach punch and the only notable opportunity to switch in is on an immune psychic attack. Unless you're absolutely adamant your opponent will use a psychic attack don't switch in with sharpedo, ever.