I feel like the most obvious difference is that one of their...tiaras? has an actual string in it, while the other appears to just be imbedded in the skin.
No choice for it then...
This is the fake one!!
The ELS' weakness is the folding chair!
"Pipe chair".
You rascal—!
I have trained you too well— ugh!
Is that so...
Strike it with this chair, and the answer will be revealed in due course.
-ish
Look, look!
It's all pointy in those ELS‑ish places!
ELS-ish
ssschik
Oh, but still...
It could be an idiosyncrasy of the animation director, or a bure motion blur effect introduced in the animation. Something like that.