A vampire bat flies back into his cave after a big night...he has blood all over his face. He perches himself on the roof to try and get some rest, but before too long the other bats smell the blood, and start to gather around him.

They ask feverishly where he got the blood from. Knowing that they will not let up till he tells them "OK, follow me!".

He flies out of the cave, across a valley, over a river into a dark forest. Deep in the forest he stops, all the other bats gather round in an excited frenzy.

"OK", says the bat, "see that big oak tree over there?".
"Yeah, yeah" reply the other bats, drooling in anticipation.
"Well I didn't!" said the bat.