Change your preferences here.
Deals damage and has a 10% chance to lower the target's Speed one stage.
Bubble is much too weak to be worthy of competitive use. BubbleBeam is undisputably superior, barring PP, and even then, almost everything would prefer to use Surf or Hydro Pump due to their higher Base Power.
Surf is a more powerful and reliable alternative with no added effect.
Hydro Pump is a far more powerful alternative with lower accuracy.