“(a) In general.—Whoever, whether or not acting under color of law, while in disguise, including while wearing a mask, injures, oppresses, threatens, or intimidates any person in any State, Territory, Commonwealth, Possession, or District in the free exercise or enjoyment of any right or privilege secured to him by the Constitution or laws of the United States, or because of his having so exercised the same, shall be fined under this title, imprisoned not more than 15 years, or both.
Section 1363 of title 18, United States Code, is amended by adding at the end the following: “Whoever, during the commission of an offense under this section, wears a disguise, including a mask, shall, in addition to any term of imprisonment otherwise imposed under this section, be imprisoned for 2 years.”.
Man, cosplayers are gonna be pissed.
Really though, this sounds almost silly considering how broadly it is formulated. Hell, you could count Halloween costumes as a 'disguise'.