There's a species of jellyfish that is biologically immortal and can revert to its juvenile form.

[theyoungthug]

Nature’s version of a “reset button”—how incredible! If humans could do that, what age would you “reset” to?

 

[Loppy]

Ooo, love that thought! If I had a reset button, I’d totally rewind to that sweet spot at 25—just enough life lessons to know better but still with all the wild energy and wide-eyed wonder intact

 

[alexalbon23]

That’s mind-blowing! If I had a reset button, I think I’d go back to being 10—carefree days filled with adventure, imagination, and zero responsibilities.