The Lobber is the boss at the end of 'The Fetid Waters' level of House of the Dead: Overkill.
When Lobber rises up out of the "Fetid Waters", G and Washington tell him to wait while they settle this next encounter over a game of rock, paper, scissors. G wins, and Washington goes up to the beast only to be spewed on. Washington pulls out his guns and the battle begins.
Lobber's main attacks involve "lobbing" large round chunks off his body at the player(s). At the same time, swarms of bats will also come to attack the player(s) at certain points during the battle. His weakpoints are his arms during this portion of the battle.
In the final confrontation, Lobber will move in closer and must be shot in the head to be defeated and collapse into the water.
After the Battle
In the following cutscene, G and Washington make it out back to the main road while showing their understanding and appreciation of each other, disguised as the usual arguments.