Having an old BMW convertible laying around to tinker with is a good problem to have. Upgrade the engine? OK, but easy. Suspension? That's beginner stuff. Delightfully insane British YouTuber Colin Furze, turned his old Bimmer into a hot tub on wheels.

Your move.

Furze has a history of cranking out ridiculous creations, which range from jet-powered bicycles and homemake hoverbikes to thermite launchers and fireworks "Deathstars." He is as entertaining as he is mad. That's why BMW turned to him for what it's calling a Mad Mod. 

Starting with a 1989 BMW 325i convertible, Colin transformed the car so it would be able to handle the coming deluge. All of the electronics have been relocated and protected. In fact, the ignition is now located up by the front windshield wipers. The cabin space has been protected so it can hold water and the engine works as a heater for the water. From there, a pair of leaf blowers were installed and mounted next to the rear top when it's stowed. They serve to produce the bubbles in the hot tub.

To fill the car, Furze and a friend drove to a nearby carwash—clever, but perhaps not ideal. Still, it achieves the goal of getting a bit of water into the cabin of the BMW. As the pair drove away, the BMW earned its sea legs without spilling a drop. They still need the bubble action. The leaf blowers fire up and the rolling hot tub continues its journey.

Eventually the pair finished their drive and wound up by the water. It's there where we're treated to a bonus feature of this old convertible. The rear trunk lid doubles up as a grill, and the pair of presenters finished the day with some freshly cooked fish and chips.

Now we just need Colin to test the car with a full load of water to see if it might be the fastest hot tub in the world.