This is kind of an oddball piece. I found it while going through some old comic book art files this past week. It's a loose pencil drawing, obviously by Kevin Eastman, drawn on illustration board.
At first, I thought it might be an alternate cover idea for issue #8 of TMNT Volume 1, but I'm not sure. It's possible that it might be an idea for a cover for one of the First Comics reprintings of those early issues in color. -- PL