Tooltip in a table

OK, so there's a Table. And a client who wants a tooltip in that grid. To show 13 additional columns (I am not kidding), and few rows.

Please confirm, that tooltip usually shows a sentence. And a short one at that.

I need to offer an alternative. "More" button? The additional information are basically extra columns, that are just secondary in importance, to the persistent columns.

Thank you for your advice.