xkcd #3317: Gravitational Square Wave
Title text:
Depending on the energy deposition I can manage, it might also be a fun prank on the rest of the Earth.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3317/


Awesome, thank you!
I was wondering, as a completely naive person, if a large enough square gravity wave would be capable of “moving” objects faster than the sites of light, where this is permissible because it wouldn’t be movement but space time bending.