Looking for the ideal Christmas gift? Look further. Even if your digital pockets are bursting with Bitcoin, the following collection of outrageous items are likely beyond your reach. It's time for our annual recap of the most extravagant, over-the-top and, in some cases, downright nonsensical examples of luxurious excess that have crossed our desks throughout the year. Here's what you can't have for Christmas in 2018.

America's most expensive house

Any real estate agent will tell you that location, location, location are the three most important factors when buying a new home. On that front 924 Bel Air Road, with its 270-degree unobstructed views of the Los Angeles area, certainly delivers. But the humble abode also has a few other things going for it, including four-lane bowling lane, 40-seat 4K Dolby Atmos home theater, five bars, 21 bathrooms, three gourmet kitchens, a private showroom stocked with cars and motorbikes valued at over $30 million, and a deactivated Bell 22A helicopter used in the TV series Airwolf – and we're still barely scratching the surface.

Dubbed "Billionaire," there are no prizes for guessing the target market for the house. It was listed for sale at US$250 million in January, making it the most expensive house for sale in the US. Unfortunately for Bruce Makowsky, the real estate developer who enlisted some 250 workers to build the structure over a period of four years, the house is apparently still on the market.

The world's biggest 4K widescreen TV

Sure to not look out of place in any of Billionaire's 12 bedrooms, the C Seed 262 lays claim to being the world's biggest 4K widescreen TV. Austria-based C Seed made its name with big screens intended for the outdoors, but in making the move to indoor units decided not to scale things down. In fact, the company went in the other direction, with the TV's 262-in (6.65-m) screen leaving the 201-in (5.11-m) C Seed 201 outdoor TV in its shade. Since the TV would leave a massive black rectangle in the room when it's switched off, it comes with a motorized custom cover that will make the screen look like a more tasteful painting instead.

What's the price for this televisual behemoth? A paltry $549,000, not including the optional installation fee of $38,500.

A creepy clock

As a species we seem to be obsessed with time, and even though it's found on just about every mobile device nowadays, there's a subset of humankind that still hanker for exceedingly complicated mechanical timepieces costing a small fortune. With eight articulated legs and inner working contained within a bathysphere-like bubble, the Octopod is definitely exceedingly complicated. And at $36,000 it's definitely expensive. It's also impractical, potentially nightmare-inducing and largely unnecessary. Luckily for those of us who can't afford a $36,000 clock, a $10 Casio will do the same job.

An alien time capsule

In a similar vein, it's a case of Roswell meets Rolex in this exquisite timepiece fit for an alien overlord. The Horological Machine No. 6 (HM6) Alien Nation does away with the Earthly notion of a glass case and replaces it with a 12 handcut blocks of sapphire crystal that were polished for up to 510 hours each to achieve the perfect fit (not counting the hundreds of hours lost due to breakages). Along for the ride are five delicate alien micro-sculptures made of white gold who watch over the intricate workings of this otherworldly timepiece. Even if you have a lazy US$500,000 lying around, this ship has flown – only four examples of the HM6 Alien Nation were made and they've already been sold to a single collector.

A million-dollar motorhome

If "Did I pack the Porsche 911?" is a phrase you're likely to mutter when gearing up for your next camping trip, this humungous motorhome might be for you. The Mercedes Actros-based Signature 1200 is 39 luxurious feet of road-going getaway that packs a 523-hp six-cylinder turbo diesel, air suspension and a suite of driver-assist technologies.

Unsurprisingly for an RV that starts at €773,500 (approx. US$922K), the bespoke interior can be tricked-out with all the comforts of home, and given parking on those poky European streets could well be a challenge, there's also the option of a 360-degree camera system. The icing on the cake is the pop-open tailgate with hydraulic ramp that caters for your Porsche 911, Mercedes SL or Mini Cooper. That's what we call last-mile transport!

Batman's bicycle

Bicycles first gained popularity as utilitarian people-movers, and although it might have two wheels and rely on pedal power for propulsion, the Pluma Track Bike is definitely not within reach of the common man. Based on a concept design by Portuguese industrial designer Nuno Teixeira, the Pluma features an aerodynamic fairing that covers the rear wheel. In fact, the aerodynamics of this bike are taken to such an extreme the wheel enclosed within that fairing was also chosen to minimize drag. If you're hoping to see how the bike performs we have bad news – it was built as a one-off for a Geneva-based client.

A floating palace

There's really no better platform for an uber-luxurious design concept than a superyacht, and this sumptuous effort from Benetti should certainly pique the interest of anyone with enough money to make it a reality. Along with your standard trappings like a freshwater pool and spa, the flowing lines of the 253-ft Se77antasette concept harbor the master of all master suites – a 100-sq m (1,076-sq ft) apartment, with another 140 sq m (1,507 sq ft) of private outdoor space that can't be accessed from the rest of the boat. A welcome addition to any billionaire's private marina.

Tomorrow's supercar

As a concept, the Terzo Millennio dreamt up by Lamborghini in collaboration with MIT researchers isn't something that will be appearing in anyone's garage this Christmas. But as a thought experiment intended to inspire the engineering breakthroughs for the next generation of electrified supercars, there's a chance some of the car's technologies, such as supercapacitors replacing conventional batteries and a self-healing bodyshell that doubles as energy storage, may appear in a future Lamborghini. But who are we kidding? We won't be able to afford one of those either.

An underwater Aston Martin

Designers over at Aston Martin have been keeping their pencils very sharp of late, producing stunning creations like the Valkyrie supercar and the sleek AM37 yacht. For us though, the pick of the bunch is the Project Neptune submersible, a vehicle that takes Aston Martin's signature styling and plunges it below the waterline. A collaboration with submersible specialist Triton Submarines LLC, the three-person Neptune is still at concept stage, but even if it emerges from the depths it will likely remain in that rarefied realm frequented by megayacht-owning billionaires.

Chocolate like no other

There are three types of chocolate: dark, milk and white. That seemingly immutable law of nature was broken in September with the announcement of a fourth family member – ruby chocolate. Developed by Switzerland's Barry Callebaut company, ruby chocolate's distinctive color and flavor (described as a "tension between berry-fruitiness and luscious smoothness") come naturally from the ruby cocoa bean. It's not exorbitant cost that's keeping this new breed of chocolate from ending up under your tree this year though – it's just the fact that ruby chocolate won't hit the market until 2018.

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