Worm-tainted farm animals infect ocean life, spreading zombies across zone boundaries through connected water.
Samantha observes undead seal and crab young, flopping zombie fish, and zombified seagulls on the Cuban shore. Carl infers that an infected farm animal entered the ocean, bit marine life, and initiated a cross-species chain.
Although ordinary regional borders block most movement, the quest confirms the ocean connects the zones and carries the highly contagious outbreak everywhere. The resulting weak undead population becomes ideal host material for evicted demons.
A chain of infection moving from a zombie farm animal into fish, seals, crabs, and gulls across an ocean map.
The ocean outbreak merges the earlier farm disaster with the demon event by supplying countless mobile shells.