There is a difference between a hoax and a prank.  A prank, however, can turn into a hoax.  Hoaxes are not funny.  Jokes and pranks are often confused with hoaxes.  A hoax can mimic one of the other two.  So, it becomes easy to not know where the line between them is.

UFO’s, crop circles, urban legend, mermaids in Zimbabwe, and balloon boy’s prank are examples of where and how hoaxers are practiced. 

Practical jokes on April Fool’s day or in other situations are purely prank activities.  A Hoax is intended for malicious misdirection.  It is fraud.  The word itself is derived from ‘hocus’ (as in hocus pocus) which means ‘to cheat’.

Hoaxes tend to exist where there is doubt to begin with.  Lack of enough proof, too many uneducated guesses and a refusal to believe are all elements that make the possibility of hoaxes viable.  Those who perpetrate hoaxes in those cases are vicious.  They stunt the growth of understanding and seriously cost other people time, money and reputation.

People forget that UFO stands for Unidentified Flying Objects.  This category includes secret terrestrial aircraft as well as probable space alien ones.  The torture and experimentation probably comes from the secret terrestrial types since it is otherwise illegal and immoral to do this publicly.  And, if multiple universes actually exist… the same concept applies.

As far as crop circles are concerned, there is a science devoted to it.  A legitimate crop circle has to meet specific qualifications to be deemed authentic.  This doesn’t rue out space alien graffiti.  Science has currently ruled out an earthly source for authentic crop circles.

Urban legends are perhaps a gray area where hoaxes are concerned.  Any good lie has a small kernel of truth.  However faint it may be.  Generally, urban legends are for the entertainment that comes from fear.  These are rarely vicious.

Mermaids in Zimbabwe might be a combination of folklore and some actual unknown sighting.  It’s hard to say.  This could be similar to an urban legend, except that it is taken more seriously and actually believed by large numbers of people.  A number of water projects were seriously delayed as a result of this fear/culturally based belief.  Local folklore remedies seem to have fixed the problem.  But, it has not been proven that actual water spirits or mermaids exist or not.

The balloon boy’s prank turned into a hoax due to the seriousness of the offense.  The boy sent up a weather balloon, and he then hid in the house while refusing to come out when called by his parents.  The parents thought the child had gone up with the balloon.   It is unlikely that this child will have the confidence of his parent’s trust for a while.  This is the nature of children.  That’s why important or dangerous items need to be securely locked away from them.

Hoaxes aren’t funny because they aren’t intended to humor other people.  They are often malicious and harmful.  The are, at the very least, obstructive or costly to someone.