From publisher blurb:
Did too many players show up for game night? Is there someone who can't decide on a single character to play as? Have you ever just wanted to play as an endless stream of near-faceless minions thrown relentlessly into the meatgrinder that is Dungeon World and just keep playing the game? Then the Guest Star is the playbook for you!
The Guest Star is a playbook for the Dungeon World roleplaying game, designed around playing as side characters or NPCs. You join in as some kind of helpful character, be it a local law enforcer, an emissary from the guild, an elf travel guide - whatever suits your needs! But the world is a dangerous place, and you can expect a character like this to not last very long - but that's fine, because this playbook is built around dying to give the important players helpful benefits, and then coming back as a new side character!
This playbook has a variety of mechanics not found anywhere else in Dungeon World. Give it a look!