Change your preferences here.
Deals damage and has a 10% chance to lower the target's Speed by one stage.
Bubble is much too weak to be worthy of competitive use. BubbleBeam is 100% superior, barring PP, and even then, almost everything would prefer to use Surf or Hydro Pump due to their superior power.
Surf is a more powerful and reliable alternative with no added effect.
Scald is a more powerful and reliable alternative that may inflict a burn on the opponent.
Hydro Pump is a far more powerful alternative with lower accuracy.