Azumarril. From a combined effort of myself and my brother grinding xD
It was on Ruby, and now it's currently residing in FireRed.
Could upload it to DPPt, but it's not natured/ev'ed, plus it has Surf, Waterfall, Hydropump & Dive as attacks, so it'd probably end up sitting in a box.
Man, that was like, 7 years ago :O