Oil

Oil is an enemy in the game Donkey Kong on the Game Boy. It appears in stage 1-1 in the Big-City for the first time, which is after stage 0. The enemy consists of fire in a tin resembling an Oil Drum with the text "oil" written on it. It floats up and down in place without trying to attack Mario, but touching it is deadly. It can be defeated with the hammer. Oil reappears in Mario vs. Donkey Kong and behaves the same way.