The OMS Devilfish sub, also known as the Devilfish OSM, was an underwater vehicle used and distributed by the Galactic Republic. It was used in the Battle of Mon Cala. This was used for extensive purposes by the republic, Mon Calamari, and, eventually, the Quarren forces of the planet Dac after a Separatist invasion engineered by Riff Tamson. It was specifically used and introduced to the planet Dac during the initial Republic backup of the Mon Calamari forces during the unoficial Quarren threat. After the Quarren attacked under the influence of Riff Tamson, and reinforced with Separatist Aqua- droids, the Republic task force along with the rest of the Mon Calamari defenders, was defeated. After the survivors of the attack contacted the Jedi Council, a Gungan army was dispatched to Dac from Naboo. The Gungans incorporated the use of abandoned Devilfish subs in their attack, and, despite the fact that their counterattack was larger than the original Republic reinforcements, they too, were defeated and taken to enslavement camps. During the execution of Prince Lee- Char, the Quarren, Mon Calamari, and Republic/Gungan forces rebelled against Riff Tamson and engineered the use of Quarren- occupied subs to defeat the Aqua droids.