The definition of a threat hinges on two conditions that must be present: ability to inflict harm and intent to inflict harm
In this case, no ability was present unless you believe that somehow balloons can be used to cause bodily harm.
In this case, no intent to inflict harm was present unless you believe that somehow, walking down the street in a costume automatically infers a threat. If that is the case, Halloween should be a very fearful time for you.
Further, when the clown turned to run away, all threats real or imagined were removed from the situation. Do you know why police are prohibited from shooting a fleeing suspect? Because there is no threat by the fugitive.
Yeah and nobody conceals weapons.