The other answer to this is correct, but a little more detail in case you're interested:

^W is a control code. This specific one represents the keys ctrl+w, a keyboard command in Vi and Bash among other things. It deletes the previous word. You often see something similar with ^H as well, which is a single-character backspace. https://en.wikipedia.org/wiki/Backspace#^W_and_^U has some more information about these.

Some people use them more to make visual jokes in written text, more or less the same way you'd use strikethrough formatting in text.