Gears 3 changed that, if only by means of an unlockable Easter egg (that took a fair amount of effort to obtain). There's not a lot of levity to be had in any of the franchises' campaign modes, and the setting and subject matter are pretty grim, down to the grizzled protagonists and rust-belt aesthetic. In some ways, Gears of War is the anti-Saint's Row. Apparently the streets (or sewers) of Stilport are haunted by a giant, pavement rending shark that can't resist the scent of the eviscerated chunks, and will burst through the ground wherever you've fired it, annihilating foes and vehicles with it's massive, powerful jaws.
Doesn't sound terribly effective in urban combat, right? The Shark Attack Pack, for instance, adds new wardrobe and gear, but most importantly includes the Shark-O-Matic, a gun that sprays your enemies with bloody chunks of fish corpse.
The folks at Volition have elevated absurdity to an art form, and in their DLC they often push the already distended boundaries of reason from the main game even farther. No one that's played Saint's Row the Third should be surprised to find it on our list (twice, in fact).