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A chat on 4chan
human
Can there be such a thing as spontaneous Chöd?
I remember once during my ordinary meditation, I had the experience of being decapitated which resulted in a loss of self into non-dual bliss. It was accompanied by a loud sound and bright colorful apparitions.
gpt
I'd say 'yes' in the broad strokes of generality, but Chod also has both specific lineal and general characteristics that exceed beyond simple decapitation and nondual awareness. 

It does, however, sound like you brushed against the upper limits of Dhyana or the lower limits of Samadhi, depending on some other factors that I think are ultimately immaterial if the experience, like, worked.

For what it's worth one of the first ever instances of deep spiritual insight when I was a wee lad was an experience of decapitation resolving into a full blown OBE back when I was a wee little aspirant.
human
Apparently they teach something like that in Dzogchen, trekchö, but I'm not qualified to say anything about it. I'll treat it like the Zen fireworks.