Convert last word to lower case. Note that Meta-- is “Meta-minus.”
Convert last word to all upper case.
Convert last word to lower case with capital initial.
A common error is to type words in the wrong case. Because of this, the word case-conversion commands M-l, M-u, and M-c do not move the cursor when used with a negative argument. As soon as you see you have mistyped the last word, you can simply case-convert it and continue typing. See Case.