Both are used now. Future Twilight is used for comic spoilers, while Alicorn Twilight is used for episode spoilers.

I honestly think the “spoiler alert” one is better because it fits.

How about alternating between the two?

@AdrenResi  
haha i have the doo hickey thingy magigy to translate that

@ponymatt  
也不是我的语言 ：（  
Ah I’m kiddin

@왜,알아서 뭐하게  
NOT MY LANGUAGE!

@Background Pony #1054  
down

The first one, future Twilight.

right

@ED-SKaR  
ヽ༼ຈل͜ຈ༽ﾉ PRAISE THE JONTRON FOSSIL ヽ༼ຈل͜ຈ༽ﾉ

Voting for democracy mode  
@x567  
@aza191  
@Background Pony #1054

@aza191  
up

@x567  
Left

Right

Future Twilight makes more sense for a spoiler.
 
It’s also an awesome picture.

One on the right.

@EHAN  
…  
(pulls picture out of the box, rips it in two, puts puts the right half back)  
There.  
(polishes left half)

@nicky  
好吧

左

win is 2

@aza191  
(Puts the picture in a box)
 
Everything you own in the box to the left

To the left, to the left…  
To the left, to the left…

@F  
I did put up the picture on my comment

I want an animated gif of alicorn Twilight dressed like future Twilight winking with either eye.

@EHAN  
We gotta dig deeper.