Little People
S01E08 - Airdate: 1999-04-05
Runtime: 30 min
Dilbert discovers that the office is inhabited by a race of former employees who have been "downsized" (literally shrunken down to size after they've been laid off) after finding all of his belongings used, the dry-erase markers disappearing, and X-rated websites on his computer.
Episode details and rating from TVmaze.