First time I've seen this in person -- my SE's flyback is unhealthy, it's started emitting a funny noise and has a very obvious purple glow emitting from it.
It's quite pretty, but looks just a bit spicy / dangerous so I'll replace it.
I have a clear case and it is tempting to keep it but alas, probably not very safe to do so.
But yeah, purple glow emitting flybacks should be a thing. I did offer it up to @cheesestraws as something he could keep running from mains electricity on his window sill… but strangely enough that offer was refused.