A bat teaches his three children how to suck blood…
After teaching them, he orders them away to test their abilities
The first of the children return, filled with blood on his mouth, and says
“Dad, do you see that cow?”
“Yes, I do son”
“So, I sucked it’s blood”, the first one replies
The second one comes later, with even more blood on his face, and says
“Dad, do you see that horse?”, he asks
“Yes, I do, son”
“So, I sucked its blood”
Finally, the third one returns, with even more blood on his face, and says,
“Dad, do you see that wall?”
“Yes, I do, son”, replies the father
“I didn’t”