Is it Her Imagination by *Tendrak on deviantART
Tendrak combines a peanut butter and jelly sandwich with a breast-enlarging alien remote control unit, to achieve very interesting results. Is it her imagination, or are they getting bigger?
In the Japanese anime "UFO Ultramaiden Valkyrie", Akina Nanamura is a character who is very insecure about her flat chest. In this episode from the second season, the character of Hydra makes a wish for Valkyrie to cause Akina's breasts to become very large. And they do. For a while, anyway.
[UFO Ultramaiden Valkyrie - Season 2 
The year was 2001 and a comic book was released with such a transparent premise that even breast expansion fans were left groaning. Our heroine - Jules - dresses like a Catholic schoolgirl. When she discovers a reality-altering alien artifact and issues it a clumsily-constructed command, it winds up giving her absolutely huge tits that burst right through her blouse.
Also, the alien artifact gives Jules the ability to manifest other dangerous machines on her body, transforming the young woman into a huge-breasted weapon of mass destruction.
Slated to run six issues, the publishers never managed to release the final three. Periodically, new rumors arise that the comic's three issues will finally be released. Yet six and a half years after issue three's release, it seems unlikely that the comic will ever be completed.