(a) Any person who throws any substance at an off-highway motor vehicle or occupant thereof is guilty of a misdemeanor and shall be punished pursuant to Section 42002 by a fine of not more than one thousand dollars ($1,000) or by imprisonment in the county jail for not more than six months, or by both the fine and imprisonment.
(b) Any person who, with intent to do great bodily injury, maliciously and willfully throws or projects any rock, brick, bottle, metal, or other missile, projects any other substance capable of doing serious bodily harm, or discharges a firearm at an off-highway motor vehicle or occupant thereof is guilty of a felony.