Kirin and ponies

[ManaMinori 4,149]

Does anyone recall "Feeling Pinkie Keen", where Twilight had become so enraged that her mane and tail spontaneously combust, and her coat took on a new hue? Also too, Ceestia has been shown, both in comics (Reflections), books (JotTS), and episodes (Daybreaker) to become enraged enough to spontaneously combust. How much of their bloodline carries Kirin \Nirik  genes to allow for them to transform with extreme anger as the trigger?

[Steve Piranha 29,496]

I think Twi’s was just a visual gag. Cellie is more justified, with her connection to the sun.

[Ganondorf8 11,714]

8 hours ago, Steve Piranha said:

I think Twi’s was just a visual gag. Cellie is more justified, with her connection to the sun.

Essentially this. We haven't seen Twilight explode like that in years and Celestia's situation was what could happen if she were to succumb to darkness like Luna did.

[cuteycindyhoney 13,339]

9 hours ago, Steve Piranha said:

I think Twi’s was just a visual gag. Cellie is more justified, with her connection to the sun.

Just like when she drank hot sauce in the first episode, and shot flame out of her mouth. It wasn't quite a factual event, but  more of just a visual joke representing how she felt.

[Misty Shadow 8,200]

"There's Kirin blood in me." - No one 

It's just a cartoon visual gag like others have already pointed out. As well as a gag that hasn't been done with Twilight since Season 1, long before introducing Kirin to the show was even a thought at that.