Here are a few examples of metaphors for something that spreads quickly:
- "The matter became a wildfire"
- "The cancer cells were invasive"
- "Those were unwanted/incorrect rumours"
- "The ant colony soon asserted its dominance"
- "The pandemic seemed unstoppable"
Here are a few examples of similes for something that spreads quickly:
- "(Something) spread(s) like wildfire"
- "(Something) spread(s) like cancer cells"
- "(Something) spread(s) like unwanted/incorrect rumours"
- "The army spread like an ant colony"
- "The terror spread like a pandemic"
I hope this helps!