The grotesque is the expression of the estranged or alienated world, i.e. the familiar world is seen from a perspective which suddenly renders it strange (and, presumably, this strangeness may be either comic or terrifying, or both).
The grotesque is a game with the absurd, in the sense that the grotesque artist plays, half laughingly, half horrified, with the deep absurdities of existence.
The grotesque is an attempt to control and exorcise the demonic elements in the world.