Noah's Ark

This tile will be set aside and replaced with the ark. Each GM turn 1 random tile will transform into an ocean tile, and all ocean tiles on the board will transform 1 adjacent tile into an ocean tile. This will continue until all non-ark tiles are ocean.
During this apocalypse, if you end your turn in an ocean tile, you suffer 15 damage. Once the board is full of ocean, you also get pushed back to an outer layer.