There isn't a single "cosmic accident" responsible for all irregularly shaped galaxies. Instead, their formation is typically a result of a combination of factors and often involves gravitational interactions with other galaxies.

Here are some of the key factors:

* Tidal forces: When galaxies pass close to each other, their gravitational pull can distort each other's shapes, pulling out long streams of stars, gas, and dust known as tidal tails.

* Mergers: When two galaxies collide, their stars, gas, and dust mix and merge, creating a chaotic and often irregular shape.

* Smaller galaxies falling into larger ones: Smaller galaxies can be pulled into larger ones, disrupting their structure and adding new material to the larger galaxy.

* Internal processes: Sometimes, irregularities can be caused by internal processes within the galaxy itself, such as supermassive black holes at the center causing jets of gas and particles that distort the shape.

It's important to remember that galaxy formation is a complex process, and the specific circumstances leading to an irregular shape can vary significantly. However, the gravitational interactions between galaxies are often the primary driving force behind their irregular morphologies.