"More humungous" is an already quite extreme term, but if you really need to emphasize the size or scale of something even further, there are a number of synonyms you could use. For example, you might describe something as "monstrous," "colossal," "gargantuan," "titanic," or "enormous." Other options include "immense," "vast," "giant," "mammoth," "jumbo," or "whopping." Depending on the context, you could also use more playful or informal terms like "ginormous," "mega," or "gigantic." Ultimately, the right choice will depend on the tone and style of your writing or speech, as well as the degree of exaggeration you want to convey.