Crappy sound effect?

This onomontoPOWia from "Jack Kirby's Teen Agents" will surely rank as one of the all-time greats ever given to a grateful humanity:


Yes, that's "BA-THROOM", as in the sound of your local toiletry exploding in a fiery, drawing-filled, white-outlined concussion of methane-fueled fury. I don't know what might cause the "BE-DROOM!" effect, but I'd darn sure pay to find out.