Return a Row Entry bases upon Cell Value

I have a unique issue that I am wondering can be solved via a Macro or a formula. I will try to state it as easily as possible. In a workbook I have 2 worksheets, in my example I will call them "Categories" and "Layout".

In cell M2 of "Layout" I would like to return the value of the cell in Row 1 of worksheet "Categories" that corresponds with the value of cell D2 in the worksheet "Layout". So simply put if Horse is in cell D2, I would go to worksheet "Categories" and search for the word Horse, once found, I would locate the value in Row one of the same column, and place that value in cell M2 of the worksheet "Layout", so in this example we see Horse is in Column A, and the value in cell A1 is "Animals" so I would like "Animals" returned in cell M2 of the "Layout" worksheet. And so forth and so forth. A value will never be in more than one column.

Also in my example the worksheet "Categories" end in column M, but in actual workbook it can go over 50 columns and down 1000.

Is this possible

Thanks for any assistance!
-Staci

Put this array formula in M2:

=INDEX(Categories!$A$1:$M$1, MIN(IF(Categories!$A$2:$M$8=D2,COLUMN(Categories!$A$2:$M$8))))

...and confirm it by pressing CTRL-SHIFT-ENTER. "Animals" should appear. Now copy that cell down the column.