Outlaw is not a creature type. If an effect asks you to choose a creature type, you can’t choose outlaw.
Shoot the Sheriff
The only deputy in the Outlaws of Thunder Junction release is a Mercenary, so no, you cannot shoot the deputy.
A card, spell, or permanent is an outlaw if it has the Assassin, Mercenary, Pirate, Rogue, or Warlock creature type. It doesn’t matter if it has more than one of those creature types; as long as it has at least one, it’s an outlaw.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Dan Black
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
