Crystal Flash

The Crystal Flash is a technique used in Super Metroid to regain health outside Energy Charge stations or your ship. According to a Nintendo Power magazine exclusive storyline released near the release of Super Metroid, when the Chozo adopted young Samus Aran after she was orphaned by a Space Pirate raid on Zebes, they had infused her with Chozo blood, endowed her with the Power Suit, and taught her one of their greatest technological achievements: the Crystal Flash technique, to be used as a last resort measure for healing. The technique creates a unique spheric cocoon around Samus, allowing her to absorb all of the energy of the Power Bomb, healing completely out of critically low health.

It's performed by following these steps: This will result in Samus rising into the air in a ball of light, suitless, while her energy tanks rapidly refill.
 * Have 49 or less energy, nothing in your reserves, and at least 10 missiles, 10 Super Missiles, and 11 Power Bombs.
 * Morph into a ball
 * Hold down + aim up button + aim down button (default L and R) + fire button until the Crystal Flash starts.

Notes: Power Bombs must be selected for this Technique. Also your ammo supply will drop as the Crystal Flash is performed.