It'd be better to just print this to world.log because 
There are procs to do this for you with some nice formatting

error("[M.type] (played by: [M.ckey]) ran is_special_character().")

It'll output something like "### error: /mob/living/silicon/something (played by: carnwennan) ran is_special_character()" in the runtimelog so coders can see it.