Deep Sea Reg Rubbadubbers : Season 1 Episode 13

Reg is tired of standing guard for balls that fly out of the bath as the Rubbadubbers are playing an underwater ball game. He can't join in the fun. If he goes in the water his joints will rust. When Reg wishes he could go underwater, he is transported to an underwater kingdom to protect a treasure from a monstrous thief. After encountering the thief, Reg wishes he were back on dry land.