The marker appeared in T13, which, if I recall correctly, was its first appearance, though this was not the first compulsory duty to use it. Other duties used stack mechanics, but with different marks, such as the purple lightning mechanic in the Five Headed Dragon fight in World of Darkness.
In case people haven't seen the marker before, I like to do this:
which will put a big stack of glowing waymarks on me. Or t, if you want.Code:/micon a waymark /waymark 0 /waymark a <me> /waymark b <me> /waymark c <me> /waymark d <me>