A Giger (like Wiger) is a ginger (or German) person who acts like a black person. Using there speech, wearing there cloths, driving there cars, and attempts to hang out with actual black people (who, most likely, dont like him).
Alex:Oh no... here comes jones, hes such a giger
jones: Yo wassup ma brothas, where yall been, man, im trippin some balls here arrrriiiight!!!