Car manufacturers often build prototypes with wacky experimental designs that never make it to production and are never shown to the public. Last year, Porsche bucked that trend by revealing several secret concept cars and now BMW has followed suit.

BMW recently showed off two concept cars for the first time. One of them is a 1996 BMW 7 Series concept with a gigantic rabbit-tooth grille like the one on the new 4 Series, confirming that BMW has been experimenting with large vertical grilles for a long time. However, the video focuses on a strange SUV called the ICE. No, it doesn't stand for internal combustion engine: it's called the Integrated Concept Engineering.

Built in 2004, the BMW ICE is a bizarre mashup of an SUV, coupe, and a roadster. Specifically, the concept is based on a BMW X5 chassis with a Z4 Roadster interior that has two extra seats in the back to create a 2+2 SAC (sports activity coupe).

The concept was designed by BMW's design studio in California, which envisioned the ICE Concept as a funky coupe SUV to perfectly complement people's lifestyles in Malibu. Spotlights were added to the side mirrors, but one of the coolest features can be found at the back.

BMW fitted a retractable panoramic roof, a foldback rear window, and a rear tailgate that can be opened in multiple ways, providing space for mountain bikes and other gear for a day at the beach. Alas, we don't get to see it in action in the video.

This wasn't the first coupe-style SUV concept BMW has built, either. The ICE Concept was preceded by the BMW X Coupe SUV concept. Unlike the ICE Concept, the X Coupe was shown to the public at the 2001 Detroit Auto Show. Eventually, the ICE Concept paved the way for the X6, BMW's first coupe SUV, in 2007 along with BMW's other sports activity coupes like the X4.