Here's my MP take on the Invisible Girl. She is incredibly weak, having slightly above-normal stats, but possessing a single superpower*: Invisibility. This seems to manifest throughout the Silver Age with her being a damsel in distress. She is captured in issues: 1, 3, 4, 5, 8, 13, 14, 19, FF Annual #1, 27, 28, 31, 38, and 44. After issue #44 the frequency of her being captured lessens.
* To bump-up her Power, I also gave her the Energy ability.