I created a icon to test on a map but whenever I try to test it on the game it doesn't show the icon just a empty icon moving but it seemed to pop up when I used a pixmap icon.
If there is nothing relocating your mob at mob/Login() or client/New() (including loading from a savefile), then your location is defaulted to 0,0,0. And you need to define an icon (and icon_state if needbe) for your mob to be "visible".