The phrase "zombie onslaught" refers to a situation where a large number of zombies, which are undead creatures, are attacking or overwhelming a group of people. Full definition
Like so much good sci - fi, World War Z is a funhouse extrapolation from the world we know: Brooks's zombie onslaught throws existing international tensions (especially in the Middle East) into bloody relief. (vulture.com)
- With a plethora of retrofitted rides and games the park has been outfitted with death traps to help players survive the next zombie onslaught. (amazon.com)
In Epidemic, three teams of players will compete to survive against the zombie onslaught. (polygon.com)