This children's game is as much of a toy as it is a game. Each player has a plastic hippo that is arranged around a plastic arena. When you push the tail it will reach its head onto the playing field - perhaps trapping one or more marbles to be pulled back to a private player marble gutter, perhaps just sending marbles bouncing around the playing field.
Some marbles are released onto the playing area; players attempt to get their hippos to eat as many marbles as possible.