Ultraman and his many kin usually have metallic red-and-silver bodies (although several color variations have been seen in recent years) and have glowing yellow almond-shaped dome eyes (although there are exceptions to both the shape and color) and various abilities, most notably to fire energy beams from various positions of crossed hands.The Ultra-Crusaders's main weakness is that they can only stay on Earth in giant form for a limited span of time, usually not longer than three minutes, owing to a limited supply of energy (Earth's atmosphere filters out solar energy). This is marked by a light on the character's body usually called the Color Timer, or "warning light," which eventually begins to blink with increasing frequency as his energy supply dwindles (and turns from blue to red).
At this stage, the Ultra beings must either find a way to recharge or finish the fight as soon as possible, or involuntarily revert to human form, or worse, risk certain death. Some say another reason for an Ultra-Crusader to recharge is because the Earth is badly polluted by humans, so Ultraman only has three minutes on Earth, but can survive long enough in outer space.
The time limit only happens inside the Earth's atmosphere but they have none of those setbacks outside.
To counter this, Ultra-Crusaders almost always merge with a human host or create a human form for themselves in order to survive on Earth, more often than not reviving a recently dead person with their own lifeforce.
