MULTIPLE TRAP.
The mouse climbs a ladder to a rooftop house, then drowns.
A ladder leads to a platform on top of a box, where a house-like structure containing bait stands over an opening. The rodent enters the structure and walks along a pivoted door until its weight overbalances the door, which swings and drops it through the opening. The rodent slides down an inclined chute into water at the bottom of the box. The door then returns to its closed position, and a spring-loaded flap at the end of the chute yields under the rodent's weight if it attempts to climb back out.
“Should the rodent attempt an escape, the extension 16 would yield under his weight, so that he could not rise out of the water. After the fall of the rodent, the door 5 has resumed its normal position so as to close the opening 21, and the trap is ready to receive another animal; thus the trap may operate indefinitely without attention.”— Frank Wójcik, from the specification
And the world did not beat a path to his door.