Combat Arms is a free-to-play multiplayer first-person shooter where in-game voice lines react to kills, objectives and other match events. The 'Unbelievable' line comes from that in-game announcer style, marking moments that feel especially surprising or unlikely. As gameplay clips moved to video platforms and soundboards, short reaction lines like this one became easy shorthand for disbelief, because they are instantly recognisable to players and need no explanation. That familiarity keeps it useful for editors who want a quick, comic reaction without slowing down a fast-paced edit.