In the book The Crafter’s Dungeon, Sandra designs and builds many unique traps. In the Crafter’s Defense game, you play as Sandra, and can create your own unique traps. As an example, check out this spider ambush. When an invader encounters a Pot in their path, the natural reaction is to destroy it. (Have you ever met a dungeon delver who could resist breaking a pot?) However, with a pack of spiders are lying in wait, it will quickly lead to their demise.
To set-up this trap for yourself, start by creating a number of Clockwork Spiders and directing them all to move to one side of a narrow gap. Next, place a Pot in the gap, directly on the invasion path. Then, instruct the Clockwork Spiders to move to a location on the other side of the Pot. Start the invasion and wait for the sparks to fly. Or, if you are impatient, take direct control of one of your dungeon monsters and destroy the Pot yourself.