Halloween -- it may be seemingly "harmless" but it is not! It is of pagan origin. Just another ritual stolen from pagan religions. True Christians stay clean from mixing pagan worship with true worship.
anything that "takes away from" or "distracts" from Christ (and his glorious coming to earth as a humble king) is, by definition, "anti-christ". Ironic too - though insignificant in reality, is that Santa & Satan share the same letters.