. . . because it (or something like it) will probably eat your car one day!
There’s more information here about the Red Giant series of metal shredders (and several more video clips).
I wonder what type of steel those rotating teeth are made of? They certainly make car bodies and engine blocks look weak by comparison. Will any better-informed readers please tell us more in Comments?
Peter
They're really more like hammers than blades. They don't so much slice something apart, but rather pound and tear it into smaller pieces.
The cast iron in the engine blocks gets battered into chunks, while the sheet metal of the car body just gets ripped apart, rather than sliced.
Here is a link showing it eating engine blocks. I thought it would be a hammer mill but it is not.
https://www.youtube.com/watch?v=oU3eEVzwe20
Probably tool steel with tungsten or boron cubic nitride inserts.
Here is a shredder site,
http://www.ssiworld.com/index.htm
Click on the "watch it shred" button.
It's a twin shaft rotary shear shredder, probably with hydraulic drive so it can quickly reverse if it jams.
Looks to me like the engines and trannys are removed first, as shear shredders don't perform well on extremely hard, tough materials.
Normally, car shredders are high speed rotary hammer mills, per drjim's comment.
The SSI website includes a VW bug being shredded but probably without the engine/transaxle.
Don