If you wil tell a song...and no one will laugh...

i will laugh to make you happy..and for all..it will be the black comedy..

A black comedy, or dark comedy, is a comic work that employs black humor or gallows humor

Because it's a dark comedy. It's funny, but not in the sense that most are. Take Bad Santa for example, one of my favorite black comedies, the main character (Billy Bob Thornton) is a drunk, a thief, and hates everyone, and the whole movie is centered around him robbing a department store. The subject matter is very dark and there really is no happy ending. This is what black comedies are usually made up of.

It is a comic that uses black humor.

A black comedy, or dark comedy, is a comic work that employs black humor or gallows humor. The definition of black humor is problematic; it has been argued that it corresponds to the earlier concept of gallows humor.

When someone will laugh till his color will change to red then purple then black from laughing ;-)

Black comedy is something in which a cruel truth is turned into comedy at the cost of some of the sensibilities. You can turn insensitiveness of Delhites to rapes into a black comedy to drive home the point. There could be laughs, but few things would make you uncomfortable.