The diving bell spider is the only member of its group to spend its entire life underwater. It carries bubbles from the surface and traps them beneath a dome-shaped web, spun between underwater plants. The bubble acts as a home, a nursery, and even a gill. It automatically replenishes its own oxygen, sucking in the gas from even the most stagnant of water. As a result, the diving bell spider can stay inside for a full day before needing to top up its air supply.