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