Also on the word "two" there is an extension of some type of wording that goes around-the-clock on the letter "W" that touches the letter "O" on the word "of".
Teller's stamp. That bill was on the top of a strapped pile of 20s. The tellers will stamp the strap, but they never get it exactly in the center of the strap, causing some of the stamp to appear on the note. It's damaged, not special.
I tend to agree with @rickmp , and would say that the black ink mark is a partial teller stamp made post BEP.
