A small metal disc that is roughly the same size and weight as a legal tender coin or token, but can be manufactured very cheaply. Most often used to gain entry to subway systems, although most large cities have moved on to magnetic stripe cards as tickets. It is also possible to use them in arcade video games, vending machines, and pay telephones, although most of those now have a slug rejector of some sort. Many states have laws explicitly outlawing the production and use of slugs to defraud businesses. An unfortunate side effect of a slug is that it can jam the machine, rendering it useless until someone can unclog the coin chute.