Okay, so here's a cunning plan for the Goblins:<br/><br/>Use chalk to sketch a math problem on the wall. Use Prestidigitation to make it look like we've enchanted the ropes, and tell them that we've enchanted the ropes to release them when they get the correct answer to the math problem, so they'd better get it right before a carrion crawler comes along and eats them.<br/><br/>Either it'll take them a while to get frustrated of giving random answers and try to break free (at which point we're long gone), or in the ultimate crash course, they figure out both literacy and mathematics and go on to either get their own side adventure, or become recurring villains.<br/><br/>Who's with me?