On a farm out in the country lived a man and a woman
and their three sons. Early one morning, the woman 
awoke, and looking out of the window onto the pasture, 
saw that the family's only cow was lying dead in the
field. The situation looked hopeless to her--how could 
she possibly continue to feed her family now? In a 
depressed state of mind, she hung herself. 

When the man awoke to find his wife dead, as well as 
the cow, he began to see the hopelessness of the 
situation, and he shot himself.
 
Now, the oldest son woke up tp discover his parents 
dead (and the cow), and he decide to go down to the 
river and drown himself. When he got to the river, 
he discovered a mermaid sitting on the bank. She said, 
"I've seen all and know the reason for your dispair. 
But if you will have sex with me 5 times in a row, I 
will restore your parents and the cow to you." The son 
agreed to try, but after 4 times he was unable to 
satisfy her again. So the mermaid drowned him in the 
river.
 
Next, the second oldest son woke up. After discovering 
what had happened, he too decided to throw himself into 
the river. The mermaid said to him, "If you will have 
sex with me 10 times in a row, I will make everything 
right." And while the son tried his best, he could only
go 7 times, so the mermaid drowned him in the river.
 
The youngest son woke up and saw his parents dead, the 
cow dead in the field, and his brothers gone. He decided 
that life was a hopeless prospect, and he went down to 
the river to throw himself in. There he also met the 
mermaid. "I have seen all that has happened, and I can 
make everything right if you will only have sex with me 
fifteen times in a row."
 
"Is that all? Why not twenty times in a row?"
 
The mermaid was somewhat taken aback by this request, 
but agreed.
 
"Okay, if you will have sex with me twenty times in a 
row, then I will bring everybody back to perfect 
health."
 
Then the young son asked, "Wait! How do I know that twenty 
times in a row won't kill you like it did the cow?