You wind up and slug the goblin.
About three-quarters of the way through your punch – much too late to do anything about it – it dawns on you that this is actually a baby in a not-that-convincing goblin costume. The yelling was crying, you figure, and it probably just wanted some food. And that explains why it wasn’t moving or doing anything else. And the poop smell.
You’re relieved to have figured out what was going on here. As your fist connects, you think to yourself there were any number of ways you could have resolved this situation without violence.
Unfortunately, you didn’t choose any of those ways, and “I thought it was a real goblin” turns out to be a weak argument in court. You spend many, many years in prison, which might be a slight victory since you’re the kind of person who goes around punching babies and you didn’t even get killed.
The baby never forgives you. Which you figure it should have done, just for closure for itself.