It is hard to imagine a more cataclysmic event than the collision of two galaxies and the effect such an event has on each one as they are ripped apart. See the destructive power of collision at work in this video showing the latest Hubble imagery of Arp 142, a.k.a. the collision of NGC 2936 and NGC 2937.
Note: The video also shows stunning imagery of other colliding galaxies.
No Gentle Galaxy Collision [YouTube]