I don't think that sets completely useless. QA / SR / EQ / X-S may work with Sash, but it's been stated before... This sets not entirely new:
Rotom @ Choice Scarf
Nature: Modest
EVs: 252 Atk, 252 Spe, 6 HP
- Thunderbolt
- Shadow Ball
- Hidden Power Ice
- Trick / Will-o-Wisp
Note: It's the REAL Rotom, no stupid lawnmower or refrigerator appliance (where's the vacuum one?). Just the cool plasmatic rain drop.
Yeah, I don't think it's new but there's no analysis set that explains it. Easy as lemon squeezy, it's a revenge killer mostly. You can also come in on Shaymin-S Earth Power or Air Slash (which 4HKOs), and kill with HP Ice. Thunderbolt kills ALL Gyarados, and even Togekiss after SR. 2HKOs every standard bulky water too. Shadow Ball clears the way of those pesky frail ghosts / psychics, and 2HKOs Dusknoir. Trick when Blissey comes in, or just burn that Tyranitar switch in.
Why use it over Gengar?
1. Surprise- how many would actually expect this?
Are you kidding me? How does trick/scarf rotom have any surprise? Even in UU scarf-trick is one of the oldest rotom strategies in the book.
2. T-Bolt will kill every Gyarados, even with a Light Screen up after SR damage
Not that impressed really.
3. Resists Shaymin-S Air Slash, making it a decent counter.
Why not rotom appliance?
Why use it over Rotom Appliances?
1. More speed- outruns neutral base 90's like Porygon-Z and Roserade with a Scarf.
Porygon-Z and Roserade are not exactly terrifying. Scarf P-Z already has a huge list of counters better than this guy. It's set up fodder for DD/boah ttar for example.
2. Surprise- again, how many expect this guy to be scarfed? (maybe a lot, I don't know)
Everyone. How could you not expect it?
3. He's actually cool- One of the coolest Pokemon in my opinion, and not a stupid piece of equipment
No one gives a damn?
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I only tested it on Wifi, and did quite well.
That's because Rotom is generally a good pokemon, and this is a generally good strategy. Still I fail to see it having much advantage over appliance, and I fail to see where this is creative.