Time Lords appear human, but are different. Time Lords can live for an extremely long time thanks to their ability to regenerate.

Time Lords regenerate after suffering from mortal injury, illness, or old age.

Regeneration repairs and rejuvenates all damage. But a side effect is that it changes the Time Lords physical appearance, and they gain a some what different personality.

Regeneration can be traumatic, and can leave the Time Lord disoriented, and weakened.
"Whats happening?"

"He's regenerating, he's changing"
by Stefani Bigaran August 23, 2005
One of the more resilient enemies of Resident Evil 4. Created by injecting multiple parasites into a single human, they are nigh-impervious to gunfire, regrowing any lost limb seconds after they are severed.

In order to defeat one without pumping a dozen cases of shotgun shells or a few boxes of magnum rounds into it is to equip the semi-automatic rifle with the thermal scope and pick off all parasites under the skin of the offending Plagas motel.
"I tried blowing it's legs off, but it just flung itself at me! WTF?!"
"It's a regenerator, n00b. Lol."
by Turkish ET April 23, 2006
(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?
by Meglomaniac April 25, 2007
This brute, abnormality can be found in Resident Evil 4. It is amoung one of the most challenging enemies in the game that is not a boss. It is able to regenerate lost limbs from weapons used by Leon, and by far the most intimidating, shocking creature. The most efficiant way to annihilate Regenerators, is to use an Infrared attachment that can be found in the lab.There is also another cast of Regenerator called the'Iron Maiden' It has erect spikes from its carcass, and can prolongate its arms, and impale Leon if caught.
"OMG, KILL THAT FREAKY BASTARD!" Is a quote usually uttered by me and many others when encountered by Regenerators.
by (*ALEX*) February 24, 2006
The scariest enemy you'll meet in Resident Evil 4.

There is also a sub-species called the 'Iron Maiden' which has spikes.

You can tell when one is coming by their ragged laughing breath.

Can only be killed with a rifle rigged with a thermal scope.
This dude: Holy shite man did you see that thing? It was all laughing at me, man! Dude, I'm fucking freaked out right now.

That dude: I know man! Here, give me the controller, I'll kill it! Goddamn Regenerator bit my head off! DAMN!
by Shuxxa July 18, 2008
The super human ability to orgasm one second and grow another hard-on the next.
He regenerated and kept going and going and going even after he spuged. She was happy and peace rulled the planet again.
by grampa-p March 16, 2007