Mels Zucker's regeneration

"Oh, shut up, Dad. I'm focusing on a dress size!"

- Mels Zucker's final words

Mels Zucker, who herself regenerated from Melody Pond, underwent her regeneration into River Song within the Reichschancellery after sustaining a gunshot from Adolf Hitler, who was aiming for the Teselecta. Soon after, River expended her remaining regeneration energy to save the life of the Eleventh Doctor. (TV: Let's Kill Hitler)