In the rich text editor:
@spookiespooks
In a comment:
[spookiespooks](https://chowlings.com/user/spookiespooks)
For Names and Avatars:
In the rich text editor:
%spookiespooks
In a comment:
[![spookiespooks's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/spookiespooks) [spookiespooks](https://chowlings.com/user/spookiespooks)