Spine Defense are wearable devices designed for divers to protect them from undersea dangers on an Earth which has been enveloped by ocean. 

In this future, Earth has been completely covered in ocean due to the increased level of rising tides. The devices react with the environment to sense danger, and through user activation, acts in similar fashion to the spines of a lionfish. Spine defense can conceptually be worn on the forearms, back, and legs. When undeployed, the spines decrease drag, streamlining movement in the ocean, and when deployed, can be used for self defense, but also as a scare tactic against predators