The Polar Bear knocks out the Pawn that just ambushed and revealed this Hazard. Replace that Pawn with the Polar Bear, and return the Pawn back to its Ship.
When the Polar Bear is on the board, each player can play their Action Card for the Bear instead of for their own Pawn.
The Polar Bear acts like any other Pawn on the board and all regular rules apply to the Bear as well. Players can use their equipment with the Bear, and if it ambushes a competitor, the current player takes an Ice Mask Tile from the Stack.
The Bear is discarded if it gets ambushed, reaches the North Pole, or falls through a Hole in the Ice.