I drew some aquatic biotech ranged weapons for a project for Star Frontiersman magazine. These are biotech gear created by an alien species called the Gnatha. These are not merely tools, but they are living, breathing organisms! These creatures can swim on their own accord, while the Gnatha use them to throw deadly projectiles at enemies. Presumably the Gnatha created these living weapons  by genetically altering and splicing together different species of octopus, jellyfish, molluscs and even corals.