Inverse of M-q, an unfill-paragraph-function

Question

Is there an inverse for M-q, some kind of unfill-paragraph-function?

If I have undo data, then it\'s of course easy. What I am asking for is

Answer 1

Also see this post

http://blog.chrislowis.co.uk/2010/03/03/unfill-region-emacs.html

Which mentions the very useful longlines mode.