In Ruby, method names can be suffixed with !. These are often called “bang” methods. This is used to indicate that it is a dangerous counterpart of the non-bang version of the method.

I had always thought of “dangerous” to mean that the method mutates the underlying object and returns that object. However, these methods can differ from their non-bang versions in other subtle ways, which surprised me recently.

https://nithinbekal.com/posts/ruby-bang-methods/