Hydroid Medusa

Hydroid Medusas were massive jellyfish cyborgs combined with armor and other cybernetic enhancements developed by the Karkarodons on their homeworld Karkaris. Hydroid Medusas were used by Karkarodon Confederacy of Independent Systems Commander Riff Tamson during the Battle of Mon Cala. They were practically invulnerable, with blasters and lightsabers doing no damage to them. After causing numerous casualties, the Republic and Mon Calamari forces were forced to retreat. When Republic reinforcements arrived in the form of the Gungan Grand Army, their boomas were able to do some damage to the Hydroid Medusas.