Power Trick swaps stat-ups with the opponant. Not actual attack stats.
Say you swaggered a 300 Attack Infernape, it would then have 600 attack (+2 boost). If you the Power Tricked this Infernape, you would not get 600 attack, you would get your Shuckle's attack but with the +2 boost of Swagger.
Power Trick is basically Psych-Up but for Attack and Special Attack only.
Encore/Toxic/Rest/Sleep Talk is like the only somewhat usable Shuckle set, and by usable I mean, don't use it as it's absolute trash.
Blissey @ Leftovers
Bold Nature
Evs: 212 Hp / 252 Def / 44 Sdef
- Seismic Toss
- Sing / Thunder Wave
- Softboiled
- Ice Beam
Don't use +Sdef natures, unless you are using it in the uber metagame where it actually needs the extra SDef.
Using Bold nature + 252 Def evs, DOUBLES it's resistance to physical attacks, and despite having only 130 defence max, only two non-STABed physical attacks can actually ohko it. Those being Explosion, which beats anything not ghost/rock or steel anyway, and a Focus Punch from like 280 attack or more.
You need an attack move on it lol, or you are just set-up bait.