Rats

Since rats spread diseases and parasites, can chew through wood and tunnel about, and breed quickly, they are a danger to humanity.

A bowl Of peanut oil works well at killing them. They go into the bowl to get to the peanut oil and are then too slippery to get out again.

Some have made a quicksand trap for them. Just have a tall bucket of water and put any oil that floats on top there, put some seeds or other mouse bait on top, when they go for it they sink and drown.