an unofficial port
... that software pirates created an unofficial port of Sega's 1991 video game Sonic the Hedgehog for the Nintendo Entertainment System that features Mario instead of Sonic?
... that <a href="./Copyright_infringement" id="mwAe8" rel="mw:WikiLink" title="Copyright infringement">software pirates</a> created <b id="mwAfA"><a href="./Somari" id="mwAfE" rel="mw:WikiLink" title="Somari">an unofficial port</a></b> of <a href="./Sega" id="mwAfI" rel="mw:WikiLink" title="Sega">Sega</a>'s 1991 video game <i id="mwAfM"><a href="./Sonic_the_Hedgehog_(1991_video_game)" id="mwAfQ" rel="mw:WikiLink" title="Sonic the Hedgehog (1991 video game)">Sonic the Hedgehog</a></i> for the <a href="./Nintendo_Entertainment_System" id="mwAfU" rel="mw:WikiLink" title="Nintendo Entertainment System">Nintendo Entertainment System</a> that features <a href="./Mario" id="mwAfY" rel="mw:WikiLink" title="Mario">Mario</a> instead of <a href="./Sonic_the_Hedgehog_(character)" id="mwAfc" rel="mw:WikiLink" title="Sonic the Hedgehog (character)">Sonic</a>?