My dad's favourite joke - Harry the vampire bat So one day Harry the vampire bat gets back to his cave, with his entire face absolutely covered with blood. All the other bats are incredulous, demanding where Harry found all the blood. Harry agrees to show them. So they all follow Harry out of the cave, over the river, and through some fields, until they get to a field with a single tree in the middle of it. All the bats are impatient, saying 'Harry is the blood here? Where is it, man? Harry replied 'You see that tree there? I didn't.'