I was wondering about using Soak & an electric/ grass move. Most Pokemon that can learn Soak can't learn an electric/ grass move, and even if they can, it's not very effective. Besides, it wouldn't be STAB, and Solarbeam would be -50% in rain, so that leaves Thunder to be the most likely alternative.
I mean, you could always do something like this:
@ Big Root/ Damp Rock
Ability: Storm Drain
EV: 252 Speed, 252 HP, 6 Def
~ Aqua Ring
~ Rain Dance
so you set up Rain Dance, then soak, U-turn out, and then get a Pokemon with Thunder (w/ STAB).
Obviously, this might only be useful if the opponent doesn't switch out the Pokemon (therefore negating Soak), or only has 1 Pokemon left, and doesn't have a Lightning Rod or a x0 electric ability (if you go with Solarbeam, then Sap Sipper would negate that). And on top of all that, Lumineon doesn't have fantastic stats.
I was just trying to find a use for Soak, because it seems to be rather useless in competitive battle. Once a Pokemon is switched out, their type resets, and only when your opponent has 1 Pokemon left is that not a possibility, and even then you'd take so many turns setting it up, you might as well go Rain Dance > U-Turn > Thunder (if your opponent has no x0 ability or type). You could crow bar Mean Look or some trapping move into this, but if your opponent has U-Turn or Volt Switch, then your strategy is useless.
Is Soak only useful in game? Or has someone found it to be useful in competitive battling?