In the Shipyard Docks level in Los you can acquire a weapon called the Slugger which does 81-123 damage. Search the entire map to find a tiny alley (which there are many). This one is different, as there will be two fences as you go down. If you follow it all the way down you will find a footlocker containing a homemade laser rifle. Pick it up and return to where the fences are located. You will see that inside one of the fences is one of those ghouls with the poison on him. He is trapped and cannot get out. Kill him by shooting through the fence with the laser rifle. After he dies, you will get a message about an update on a secret. Then at the bottom of the screen where Boss names and health appear, it will read "Glowing Ghoul". Return up through the alley and a large ghoul will be there. He is easy to kill. After he dies, he drops the devastating Slugger weapon.