How does a snapping turtle attract prey?

Probably depends on the species. Some lay in the muddy bottom of rivers or lakes with their mouth open and wait for fish or other aquatic creatures to swim into it. I kid you not, that's really what they do. They have a small appendage in their mouth that wiggles and looks a lot like a worm or other small fleshy wiggly thing which small fish and shellfish may find appetizing.

They also bite your toes off when you step on/near them.