It is illegal to dress up as a priest on Halloween.

ALA CODE § 13A-14-4

Whoever, being in a public place, fraudulently pretends by garb or outward array
to be a minister of any religion, or nun, priest, rabbi or other member
of the clergy, is guilty of a misdemeanor and, upon conviction, shall
be punished by a fine not exceeding $500.00 or confinement in the county
jail for not more than one year, or by both such fine and imprisonment.

(Acts 1965, 1st Ex. Sess., No. 273, p. 381; Code 1975, §13-4-99.)