Mothership: SISTR: A Rare Geometry

A Rare Geometry is an 80+ page book with expanded rules and stats for use with the SIS/TR entity, well as a vicious starship adventure written by Justin Sirois and George Holland: 

25 rooms and thousands of ways SIS/TR can attack, infect, and hack their way through your party. SIS/TR is already a puzzle players have to solve — the ship functions as a puzzle within a puzzle as SIS/TR consumes resources, manipulates rooms, and broadcasts horror throughout the captured ship.