What are the Ultramen's weaknesses?

Despite the differences in details between the various Ultra-warriors, they all have the same weaknesses (although some Ultramen may exhibit an additional problem or two). These weaknesses include:

• Energy depletion. Each Ultra-hero has a specific amount of energy available to him or her. When that energy level becomes depleted, their ColorTimer, or "warning light," begins to blink and, usually, change color. If the ColorTimer should go out, either the Ultra-hero automatically reverts to human form, or the Ultra-hero dies. Note that, despite the name, the ColorTimer doesn't always imply a fixed time limit; rather, it's a "gas gauge." A ColorTimer can be recharged in various ways, and more often than not an Ultraman can be revived after his ColorTimer goes dark.
• Darkness. Most Ultramen get their energy from the sun. Shutting off access to the sun for an extended period can prematurely weaken most Ultra-warriors. (However, nighttime isn't usually enough to significantly weaken an Ultraman.)
• Extreme cold. Several Ultramen have shown that extreme cold will weaken them. The cold of space, however, often does not affect them adversely.