I'm trying to achieve the warp effect that you see in games like *Geometry Wars*.

![Screenshot of Geometry Wars including the warp effect](https://i.stack.imgur.com/7lOwR.jpg)

Can someone help explain what is going on here? I feel like the grid's z axis is manipulated in some way, any way, by the programmer, but is there maybe some known mathematical equation to really get the correct warping effect?

Edit: To be more specific, I mean the warping of the grid. How everything looks pulled towards the negative z axis and then bounces.