In Castilian Spanish: if you want something "wanna go outside" level of offensive: hijo de [la grandísima] puta (or hija if it's a she, in square brackets an optional reinforcer). Even if it's jokingly and to a friend' it's something you are careful to not misuse.
Me cago en tu padre/madre is a strong contender too.
I don't know if there are any geographical exceptions but as a native I've never heard "coño" directed at someone as an insult in the same way as "cunt" is, more like a (very rude) exclamation.
Entheogens have been used for millennia. I'm quite sure some people doing them before you saw their reasons "purer" than yours. Or the ones that went through a tribal initiation instead of buying from their trigger-happy dealer.
In Castilian Spanish: if you want something "wanna go outside" level of offensive: hijo de [la grandísima] puta (or hija if it's a she, in square brackets an optional reinforcer). Even if it's jokingly and to a friend' it's something you are careful to not misuse.
Me cago en tu padre/madre is a strong contender too.