(Can be used in other senses, but im just explaining this one)
From
Doctor who.
Timelords have the ability to regenerate after severe trauma or natural wear and tear. Their body will under go a complete
transformation, and although the same person remains, their appearance and
personality changes. (In other words, where a human would die, a Timelord would just change, thereby healing any injury in the process.)However a Timelord only has the ability to do this 13 times. (Doesnt matter much to them, in one life they Usually live to about a thousand anyway. Notice I said usually.)
The Doctor: I'd like to see a butterfly fit into a chrysalis case after it spreads its wings.
Polly: Then you did change.
The Doctor: Life depends on change, and renewal.
Did you see
the doctor after he regenerated?