A vampire bat returns to the cave and hangs himself upside down to sleep. The bat next to him notices blood round his mouth and wants to know where he got it. The bat tells him to shut up as he is trying to sleep.
The other bat won't shut up and in the end the whole cave is awake demanding to know.
Realising sleep is out of the question the bat agrees to show them. He is followed out by about 300 bats and after a while stops on the edge of a forest. Do you all see that large oak tree? he asks
In a high fever of excitement they all answer, "Yes, YES"
"I bloody well didn't!!" came the reply.