Prowling on the plains, clutching a vorpal blade, cometh Spaceman Spiff! And he gives a gutteral roar:
"As sure as predators devour prey, I lay waste to the landscape until everything has croaked!"
Also:
Striding across the mini-mall parking lot, cutting down all who dare stand in the way using a sharpened screwdriver, cometh (real name - formal 1st name)! And he gives a spectacular scream:
"By Odin's mighty spear, I bring darkness and mayhem with reckless abandon!!!"
-and-
Prowling across the fields, cutting down all who dare stand in the way using two hardened pitas, cometh (real name - nickname for 1st name)! And he gives a mighty grunt:
"I'm going to bruise you faster than the speed of sound!"