Whatever the reason people fear the marine iguana, they pose no danger to humans.
In fact, they're a little silly. Like humans, marine iguanas frequently sneeze to clear out their nostrils, except, instead of pollen, they're getting the salt out of their noses. The salt often collects on the tops of their heads, which results in something that resembles a wig.
This is what a marine iguana sneeze looks like.