Scalar ultralight dark matter models are very good candidates for cold dark matter (CDM). Not only do they keep the success of CDM at large-scales, but also provide a possible solution to the so-called “small-scale crisis”. I will talk about the importance of self-interactions in these models, which almost inevitably lead to the formation of oscillons. These are bound states of a large number of such particles that remain localized for extremely long time-scales. As a result, they have very interesting phenomenological properties as dark matter that I will discuss.