As seen in Rocket Sledge's video, this is Rocket League Minefield!
This plugin can only be used in Freeplay or in hosted matches through Rocket Plugin.
Small boostpads
When the plugin is enabled, small pads will throw players' cars into the air in a range of force, height and rotation (adjustable in the plugin).
Big boostpads
These are the deadly mines. A counter is attached to them, and every 6th time (based on the number of big boostpads in the field) any player picks up a big pad, the 6th "picker" will die. This can be turned off from the configuration.
Showcase
You can check out this plugin at work in Rocket Sledge's video or in my own video