Stay still and hope they don't bite

You would swear you saw something on one of those old westerns your grandfather used to watch about them biting to hold on, but not being aggressive. Like Tarantulas. So you remain perfectly still, letting them move past you at will, some actually moving over your shoes to do so.
After about a minute, it seems a large army of the creatures has gone by, but none remain. You look around and see that they're mostly gone already.
Phew! You think. That was a close one. Now what?