Basically...
Bob is an "entity" that can be found within the Jeff Shop in the Hotel, sitting next to El Goblino.
Bob is a tall, human-like skeleton with a black baseball cap, surrounded by a swarm of flies.
Bob sits next to El Goblino on a table in Jeff's Shop. Bob is never seen moving, nor speaking. Interacting with Bob will prompt the Player to hold the interact button for several seconds, afterwards displaying the text "...Nothing happens".
-The Roblox Doors Wiki