You don't have to, but it would be a good idea. They'll eventually diagnose you and get around to tracking down some antivenin without it. If you lose track o

You don't have to, but it would be a good idea. They'll eventually diagnose you and get around to tracking down some antivenin without it. If you lose track of it, it's probably more important to get to the hospital faster than trying to track it down. But if you can nab it, it'll save you time and you won't have to wonder where the spider went off to later, since many people encounter these things inside their homes.