"Shew" is the noise I imagine a Megabuster to make, or possibly "Blamm" when the shot makes impact.
Our dark and mysterious creature seems to glow when in a fury. It was an interesting effect for me to try, and I think I may use it later.
This is also my first time in my history of comic writing to ever interrupt a monologue with a sound effect. I think it turned out nicely.