I had to change your question to be Little Cup, otherwise I would have to hide it.
Eevee (F) @ Choice Scarf
EVs: 76 HP / 240 SAtk / 160 Spd
Modest Nature (+SAtk, -Atk)
- Echoed Voice
- Shadow Ball
- Hidden Power [Fighting]
- Quick Attack
The power of Echoed Voice increases each turn it is used (by 40), reaching a max of 200. And since you'll be Scarfed... Well, obviously I mean by that that you'll have to be using Echoed Voice consecutively. Works great with Adaptability boost. Shadow Ball and HP Fighting provide type coverage, while Quick Attack provides priority. Really, Quick Attack is only there due to a lack of anything else. While your Attack might not be great, Adaptability kind of makes up for that, although it should still only be used for revenge-killing. Max Sp Attack and Speed EVs (with HP Fighting that is) plus a tiny bit of bulk added. Remember, Little Cup EVs work differently.