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