A  mansion in Brooklyn’s Mill Basin neighborhood — a spaceship-like waterfront compound that was once the borough’s priciest listing — has sold for a hefty $20 million off its original asking price.

After nearly five years on the market, the final sale price was an even $10 million, as spotted in city records by the Real Deal.

The 14,000-square-foot property made a splash in 2013 when it listed for $30 million, which made it Brooklyn’s most expensive home for sale. At the time, though, it was listed with an adjacent McMansion, 2387 56th Drive. The brokers ostensibly split up the properties to make the price tags more palatable.

The main house was most recently on the market with an asking price of $13 million. 2387 56th Drive is still on the market for $4.5 million.

The owner of the home, located at 2458 National Drive, is Galina Anisimova, a Russian heiress, who bought the home for $3 million in 1996, city records show.

The purchaser is listed as an LLC, which the Real Deal notes is an entity controlled by Ryan Freedman of venture capital firm Corigin Ventures.

StreetEasy shows the home underwent multiple price cuts over the years.

The four-story home has 10 bedrooms, 15 bathrooms and many over-the-top extras.

Listing images show a domed skylight and double-height floor-to-ceiling windows. There are also two kitchens, two master bedrooms — one of which has a separate den and meditation room — and a media room.

Over 2,000 square feet of outdoor space, there’s a 1,000-square-foot swimming pool, a pavilion, a kitchen and two boat slips.

The listing broker was Tatiana Nikichina of Berkshire Hathaway HomeServices.