The goal of Snakebite is to take the crown with one of your snakes and move it all the way around the board back to where you picked it up.
A snake is only moved forward, and once it goes to the edge of the board it wraps around to the other side of the board.
If the head of a snake is on the tail of a snake from the other team, the snake is bitten, and can neither move nor bite another snake. You can move the crown if it is on your snakes head.