Usually when it comes to onomatopoeia, a sound gets turned into a word. But super-heroes have the power to reverse that, turning words back into sounds. In addition to generally involving massive amounts of violence, that's just one way onomontoPOWia is better, as you can see here:
Sure, "crutch" is misspelled on that last one, but I think if you're using your metal brain to smash out a demon's nose, you're allowed to swap a "c" for a "k" every now and then. I tried using that excuse on my English teachers in high school, but sadly they knew I didn't have a brain at all, much less a metal one. Sigh.