Alright Bruce the Gible, it's your time to get hit in the face with a water gun.
First, you should throw up a Sandstorm. Then, hit him with a Sand Attack. Finally, hit him with a Toxic.
If, on any action, he uses the move Water Spout, use Dig on that turn instead and push all the actions down the queue.
Ex: Water Spout on action 1, action 2 for Gible would be Sandstorm.