take on a life of its owntake on a life of (its) own
to no longer be controlled by anyone.
Once an earthquake starts, it takes on a life of its own.Someone imagined it, and the idea took on a life of its own.
take on a life of its own
To exist and thrive outside and beyond the control of the point of origin. An urban legend can take on a life of its own, changing every time it is retold.The accusations in the political race have taken on a life of their own, growing meaner and more elaborate every day.