Narcissists are addicted to supply and that is a well known secret but there are a million ways a narcissist will behave in order to gain it. One ridiculous tactic the narcissist likes to use is the one time messaging tactic.
The narcissist will message you asking you a question and then when you answer the narcissist, he/she goes silent
You ask the narcissist a question and he/she goes silent
The narcissist will message you to break up with you and when you go to seek an explanation because of course, such came out of nowhere, the narcissist goes silent
The narcissist will go weeks on end not speaking to you and than decide to send you a random message out of know where.
This one time messaging tactic is intentional and supply generating-beware!