[They'll immediately lift one of their massive arms to take the brunt of the blow, but their entire limb ripples from the impact, and they have to bite down a yelp. That's gonna bruise in the morning. Still, their interest has been piqued, and they'll lash out experimentally with their free hand. They don't want to hurt the boy, not really, so at best, it would open shallow cuts and tear his strange attire.]