Natsu with Lisanna, watching over their Dragon Egg. One day, Natsu found an egg in the forest east of Magnolia. Thinking it to be a Dragon Egg, Natsu took it to the guild and asked Makarov to make it hatch, but Makarov and Erza told him that he was the only one that could make the egg hatch; through love and care.
1 As a Decompression Chamberâ This is a hyperbaric chamber used by surface-supplied divers (commercial divers mostly) to make their decompression stops.  As Recompression chamberâ A hyperbaric chamber is used to treat or prevent patients suffering from decompression sickness.
dual chamber pacemaker. A pacemaker with pacing electrodes in both the right atrium and the right ventricle, which helps maintain the physiological relationship between atrial and ventricular contraction, and allows the paced heart to follow the increase in sinus rate which occurs during exercise.