This is an action toy, with some die-cast metal parts, of a science fiction/anime character or item.
From the popular Gainax anime series "Fushigi no Umi no Nadia" comes the mighty Nautilus! This "submerged version" of the 30cm-long die-cast beauty (painted a darker shade than the "surface version," linked below), created for release in Japan, comes with a Captain Nemo figure. (The all-gray Nautilus shown below is an unpainted prototype.) Features include missile tubes, a detachable core block, and a sensor probe. You'll even find a tiny Gratan in the rear hangar! Please note that the photos shown are of a prototype; the production version may vary.