A REALLY big spider with the seeming propensity to shred you tip to stern. When such spider walks, you can feel the fear through your feet, and the vibrations that it makes running after your ass. If you see one of these, you have one of 3 options.
"Hey Jack, where did matt go?"
"I dont know for sure, but that really big fucking spider over there with a leg sticking out of its mouth sure looks suspicious..."