It's actually pretty good when used in the right way.
Ability: Unaware (ignores enemy stat changes) Item: Twisted Spoon/Miracle Seed
EVs/IVs: Sp. Attack, Speed, HP Nature: Modest (+ Sp. Attack - Attack)
Calm Mind: Overall this is an excellent move for Swoobat, obviously beneficial for Sp. Attack and helps cover for Swoobat's poor Sp. Defense.
Psychic: (STAB) Really self-explanatory, due to the fact that Swoobat is Sp. Attack oriented and Psychic is the best Psychic move there is. However, you lose the benefit of your opponent's Sp. Defense decreasing because of Unaware.
Flatter/Swagger: Requires breeding with Nidoran (male) or Nidorino for Flatter. The ability Unaware takes out the risk of increasing the foes Attack or Sp. Attack since it allows the user to ignore stat changes in the opponent, while the opponent hurts itself as it would normally under Flatter/Swagger. Flatter is recommended over it's counterpart Swagger because Flatter has a higher chance of succeeding (100% accuracy) than Swagger (90% accuracy) and can hit ghost types, while Swagger cannot. However Swagger might be better though because it makes the opponent hurt itself more.
Air Slash/Energy Ball: A reliable Flying-type move (STAB), not much else too it. Energy Ball is good for covering Swoobat's Rock-type weakness. However, it is the same as Psychic in terms of losing the benefit of your opponents Sp. Defense decreasing because of Unaware.