Bigfoot
There are drub subs or narco-submarines as well! The Bigfoot submarine is one such unmanned submersible water vessel created to smuggle drugs and contraband from somewhere remote. This one was found in Ecuador in July 2010. Colombian drug cartel members were discovered to smuggle cocaine to the US via Mexico. It used sophisticated technology that evaded radar, sonar, and infrared. It was called Bigfoot since people once thought that it was nothing more than a myth.

Bigfoot
INS Kursura
The fifth sub of the Indian Navy was the INS Kursura. It spent 31 years in service and traveled all over the globe. It was used during the 1971 Indo-Pakistani War, participated in exercises with other countries, and served as a messenger of peace. It was decommissioned in 2001 and used as a public museum in Vizag. While it almost got flooded during Cyclone Hudhud in 2014, the government managed to save it.

INS Kursura