I took a smart washer to the local Mitsubishi dealer to see if it might be a standard Mitsu part - it isn't. They didn't consider it a "crush" washer either.
My drain plug also seemed to have been installed by a Sumo at the factory. After the first oil change I tried not to set it so tight, just snug. At the second oil change it was again so tight that it took a piece of pipe on a breaker bar to get it off. All I can think of is the hot cast aluminum sump expanding and squeezing the plug.
This tool is available at the car parts places for about five bucks. It is the same theory of operation as the official smart tool. I got the 65mm/67mm, 3/8" ratchet drive size (it fits both the 67mm OEM filter and the 65mm Mobil 1 M1-108).
