Taxation under gift

gud mrng scholers.....

suppose mr. X has a black money and he is planning to convert it into white. now he give this money to his frnd Y in cash and tell him that he(mr.Y) will give this money on his(mr.X) marriage to him (mr.X).

as above said Mr. Y gave money to X on his marriage.

and mr. X shown this money in his return of income as he received gift on his marriage,...

now my question is that  in return of Mr. Y  is this money gave by him as a gift to Mr. X is necessary to show?

and can IT department has right to take this money under assessment and take the detail of money as he gifted to mr.X.??????