Mister Lopez

 is a suicidal resident of Rivet City he can usually be found on the bridge tower.

He can be enslaved with the slave collar.

Unmarked quest: Suicide Watch
Lopez considers committing suicide due to the fact that no one remembers him or even cares about him, but he doesn't have the courage to do it himself. The player can either help him find a new purpose in life or push over the edge (literally if you want, but you'll lose Karma unless that's what you're aiming, for be my guest). If you wish to do so, be on the deck of the ship at 3 pm.

You can find him at top of the ship, but you'll have to enter through the stairwell and from there go up the stairs and you'll find a door that has a sign on top that says, "Bridge Tower". Once you enter inside go up the small stairs and as you walk out turn to your left or right (Depending on the position of your screen). You'll find a sign that'll say, "Marketplace". Once you have located the sign you'll see some stairs. Go into the hall then go up stairs and repeat the process 3 times til you enter a room that only has one door. Once you are in that room enter it and you'll be at the highest point of Rivet City. If you see the ledge, that is where Mister Lopez will be. Make sure you don't fall with him, though (personal experience: you might cripple both legs or, worse, death. However, that depends if you don't hit anything on the way down).

Appearances
 only appears in Fallout 3.