Online purchasing behavior is not linear, but the classic attribution model wants it to be. Instead, most leads come in via word of mouth that's untrackable. In-person chats, DMs, Slack conversations, podcast mentions, etc.
Because you can't measure those, it's called the dark funnel.
I've heard that Wyntergets all its leads through the dark funnel
A trip to a grocery store, convenience store, or gas station for the sole purpose of buying an excessive amount of junk food and sugary drinks, usually with friends. A chud run often happens late at night and ends with everyone involved hating themselves afterwards.