Rainbow Frog

Greninja @ Life Orb | Protean | Hasty
4 Attack | 252 Special Attack | 252 Speed
-> U-turn
-> Hydro Pump
-> Ice Beam
-> Dark Pulse

When you see Froakie for the first time, you expect it to turn into some sort of bubbling behemoth of a toad. Instead we got this.

Now this might not look particularly threatening, especially with Greninjas pretty meh Special Attack, but then you notice it's ability. Protean gives it STAB on everything. That's right, everything. It has 18 STABS. This doesn't make him amazing, but if you're looking for an offensive U-turner, he's definitely an option to consider. U-Turn is on the set because it's what he does best, hit with a powerful-ish U-Turn with his absurd speed and switch out. Hydro Pump, Ice Beam and Dark Pulse are to give as much coverage as they can, and all grant him new stabs.