Spacetime elasticity and negative mass

No.12582863 ViewReplyOriginalReport
In another thread discussing the warp drive some anon had what i thought was a neat idea.
If you had a mass and vanished it somehow, would there be any rebound in the distortion of spacetime? Think of how when a droplet strikes water, the surface first crators and then rushes back and spikes up.
Is this a thing? Wouldnt it need to be for gravitational waves to be a thing?