It's one of the most imaginative designs in the history of pre-manufactured spas – something that evokes films and cartoons and magic — and by the designer's admission, it came straight out of Hollywood:

"It came out of those old movies from Abbott and Costello where the cannibals boil the missionaries. I wanted it to give the impression it was hanging and that was real fire around the base heating the cauldron," says Steve Blamer of Cauldron Hot Tubs, the company that produces these cauldron-style hot tubs for the backyard.

And the illusion is convincing — each cauldron appears to sit on top of a fire pit, supported by chains that connect to three large supporting beams. In reality, the cauldron is anchored to a concrete foundation underneath the hot tub, with the heater, pipes, blower and filter located in a nearby equipment pad. (The chains and wood beams help give it an Old World feel.) The tub features teak seats and a stainless-steel liner for insulation.

And yes, that's real fire — but it does not affect the temperature inside the tub.

The most common question Blamer gets about the cauldron hot tub is, of all things, how to get in.

"They think they have to jump in it," he says. "You walk up a ladder for three steps and you step into the kettle."

Perhaps the reason no one asks about getting out is because there's no reason to leave once inside.

"I think we have a winning idea, but we're just starting out. We're excited to get going on it," Blamer says.