Old pc killer games(PLEASE FOR THE LOVE OF GOD HELP ME)

So there was this old PC game back in like 2005 to 2010 it was an online game not a disk just one you would regularly find online And you were basically the small tiny alien creature who would take over peoples bodies or even animals bodies and you would go around killing people. You could jump in and out of bodies but when you would do that it would kill the user but your whole goal was to just go around killing people you would end up at concerts or a lumberjack facility or a kitchen the FBI agency It wasn’t a super long game just something small and fun that you would find online please someone if you can remember the name of this game tell me