The apparent ingenuity of Ukraine's armed forces has repeatedly proven to be among its biggest assets in repelling the advances of its much larger neighbour's invasion.
Kyiv has made increasing use of airborne drones that explode on impact, with some notable successes - including inside Russian territory.
The latest example of Ukraine's often innovative approach to fighting the war comes in the form of an underwater drone.
According to footage released online, the Marichka is a black unmanned underwater vehicle (UUV) which is six metres long and a has a range of around 1,000km (621 miles).
It is reportedly a self-developed system made by volunteer engineers at a cost of $433,000 (£355,573) and can perform attack, transport or reconnaissance missions.
Marichka is expected to be used in suicide operations against Russian Black Sea Fleet (BSF) assets, along with other critical Russian infrastructures and establishments.