I just wrote this after watching the Madness Flashes (again):
The Corpse
A dead corpse went insane,
Mindlessly slaughtering everyone.
Suffering from endless pain,
He wielded mercilessly his gun.
His path was crimson red,
Blood was his taste.
He thought Humans were waste,
And wanted everyone to be dead.
The shells rained, no one survived,
Was that the reason of being revived?
Driven to life again by his own wrath,
Finally killed himself and ended the bloodbath
I know, there are mature lines (Blood! Oh my GOD!) but yeah, I think it's still OK.