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