On each step of the operations of the metaverse, information is written to the metaverse's memory; this is how changes actually occur inside multiverses. Ordinarily, actions performed inside a multiverse will only affect memory related to that multiverse; we call this physics. However, there are some actions, typically only accessible to a multiversal civilisation by coordinating actions over an entire multiverse, that allow actions taken inside of a multiverse to affect the memory related to other multiverses.
One analogy, though inaccurate, is if there was an 8-bit number in memory that remained between 0 and 255. If, at 255, it was incremented, a badly-designed memory storage system would set it to 0, but then set the first bit of the next byte to 1; this byte may not be part of the number being incremented, or even part of the program incrementing the number. It so happens to be that the metaverse has a similar design flaw, but much more subtle and over the scale of multiverses.
As this is not expected behaviour of the metaverse, done incorrectly, it can cause a harmful crash, damaging large portions of the metaverse or even forcing a complete reset on the xenoverse. This can be weaponised, to induce crashes in a target multiverse, but is also a risk for civilisations that have not yet built proper metaversal buffer overflow infrastructure.