The Sweet sang in their song Love is like Oxygen "You get too much, you get too high. Not enough and you're gonna die." We need oxygen to live, but it can be destructive as well with fire, rust etc.. It is the most common element on earth. When cooled below -218°C oxygen becomes a blueish, magnetic liquid.
Oxy the monster is a moody hothead. He interferes everywhere and easily loses his temper. But when the going gets tough, it's good to have him nearby, because for his friends he would go through fire any time.