SS-18 ICBM
Oscillator
Then you really cannot say players on Xbox Live will massacre you. 

For some reason my friends always kill me with dual-wield maulers, is there any way to stop them?
Yes- make sure to be very far away from anyone with a mauler.
Spike Grenades work better.
Maulers are cool, but the Shotgun kicks more butt.
If you want to teach enemies how to fly, gravity hammer works