The phrase "become rampant" can be replaced with various synonyms that convey the same meaning of something becoming widespread or uncontrollable. Some examples include "spread like wildfire," "proliferate rapidly," "explode in numbers," "become ubiquitous," "exponentially increase," "run amok," or "escalate drastically." Each of these alternatives paints a picture of something quickly getting out of hand, whether it is a disease, a social trend, or a problem that needs to be addressed. It is important to have a good variety of synonyms at your disposal in your writing to keep your text fresh and interesting.