One of the supporting characters in Robert Kirkman’s Invincible goes by the handle “Monster Girl”; her power is to transform into a huge, Hulk-like creature with tremendous strength. The drawback to her power is that it causes age regression, and so even though she’s at least in her 30s, she has been depicted as having the physical development of a girl in her early teens. In anime terminology, she’s been a classic pettanko.
There’s been a recurring gag for the last five or six issues, though. Monster Girl and her boyfriend, Robot, were transported to another dimension where the passage of time is vastly accelerated. While generations of the dimension’s natives live and die, the couple ages only very slowly, but the age regression effect of Monster Girl’s power was much less potent, so she finally grew up. And her breasts grew out.
In the first comic of the arc, Monster Girl shows up back in our dimension, no longer looking like a scrawny kid but possessing a fantastically curvy figure, complete with gorgeously enormous breasts. No explanation is given. However, over the following issues the comic has operated partly in flashback, explaining the adventures of Monster Girl and Robot in the other dimension. The most recent issue – Invincible #95 – is the first to show her breast growth, and to let you know she’s well aware of it. As she crushes her own growing breasts together, she says:
Man, I swear, if I didn’t have hundreds of years to get used to these things, I don’t know what I’d do. I mean, I spent so long as a skinny beanpole … I don’t even … I never thought this was in my future.
The artist who’s doing the flashback sequences is drawing her much more modestly endowed – big perky boobs rather than massive breasts – than the one doing the main illustration. I encourage you to check it out. This is the second time there’s been breast expansion humor in Invincible – the first was when Atom Eve had to rebuild her own body after an injury and later joked that she’d accidentally made her breasts bigger.