@blargg888  
It’s a throwback to the novel “Time Machine” where the inventor travels far into the future sees the fall of civilization and meets giant crabs that continue to thrive in the desolate world (and attempt to eat him).

Do I see a GIANT ENEMY CRAB there?

Relevant…  
http://www.fimfiction.net/story/6735/equestrias-twilight  
very sad story…

@Sonlirain  
I should have known..!

@Starswirl  
Yeah she’s lazy like that.

“Not prone to injury”
 
So that time Chrysalis blasted you into submission was just faking it?

Oh you people and your interpretation of immortality being a nihilistic tragedy…
 

i loled at the the writing on the graves especially rarity’s its hilarious

Oh woe is me I’ll live forever. I hate that trope.
 
But using it as a pick up line? Priceless.

@Millennial Dan  
Problem is according to oxford and pretty much every other dictionary:
 
“(hundreds) the numbers from 100 to 999”
 
The sole thing that proves is that a pony can possibly live more then a century, or basically that they have a human like life-span. (it does derail any nonsense about short lifespan, but it does not in the slightest prove multi-century ones)

@Background Pony  
Why should they be the only ones to be gifted/cursed with that? I don’t think that exclusiveness would really make sense. Besides, living forever isn’t nearly as bad as people make it sound.
 
@Tk3997
 
“Hundreds of years,” according to Twilight.

@Archonix  
“ the alternative – that the element bearers will all live forever – is also a possibility. And it’s one I quite like.”
 
Too bad that “the element bearers” doesn’t include their family and friends. Doubt AJ and Rarity would be happy about it.  
I prefer to think that Luna and Celestia remain the only immortal ones.

@Kanrabat  
And no number is ever given for that hence, nothing.

I find this very sweet…
 
Also I do not fear immortality, partially because I don’t really love or care anyone very much, partially because mathematics is immortal.

@supermanhulkjesus
 
Hmm putting it that way yeah they might as well have said “You will never find out!” (they did answer to a tweet with “Twilight wont outlive her friends” but your right)

@Background Pony  
If you want her to be mortal, she’s mortal. If you want her to be immortal, she’s immortal. The show isn’t going to contradict you anytime soon.

@Background Pony  
I would have so many feels

@d715
 
The staff already said twilight wont outlive her firends, if anything they will be the ones mourning her. :(

@MagnificentTrixie  
That’s really debatable as to if she’s immortal

@Etherchanter  
Never mind… I just re-read your comment again. Looks like I skipped a few words whilst reading…

@MagnificentTrixie  

 
…waitwaitwait…  
where did you get that?

@Kanrabat
 
If Granny is completely honest and isn’t getting her facts wrong, Canterlot is a very new city, only about a century old.
 
Why doesn’t anyone talk about that? What was the capital for the last 900 years or so, and what happened to it? We can infer that the original Castle of the Royal Pony Sisters was abandoned soon after Luna’s banishment, so where the hell did Celestia set up shop after that?
 
Plot holes are fun!

Cadance is a new-ish immortal, and Twilight is as well. In ten thousand years they’ll have a community going if the trend continues. It’s not so bad.

“HAH! Joke’s on you! I’ll just go shack up with my Sister-In-Law! Or Discord! Yeah, Discord sounds great. Try and pull that chessmaster stuff with him around and he’ll turn you into a frog or something. He’s probably AMAZING in bed too.”
 
“….”
 
“That’s right, I got immortal options out the wazoo! What now!?”

@Tk3997
 
Based on Granny Smith’s origin story. She was there when Ponyville was founded.  
So…