Long-lived, spatially-localized and coherently oscillating field configurations (pseudo-solitons, for example, axion stars and oscillons) can form naturally in cosmologically relevant axion-like fields constituting dark matter today or in fields at the end of inflation. When these clumps collide and merge, they can give rise to bursts of electromagnetic and gravitational waves. In this talk, I will first discuss earlier work on soliton formation mechanisms and their interactions, as well as gravitational wave production. Then, for the main part of the talk, I will focus on the production of potentially detectable electromagnetic bursts resulting from the merger of dense scalar field oscillons/axion stars in the current universe [this is based on our recent paper, https://arxiv.org/abs/2009.11337]. Time permitting, I will also discuss possible connections to Fast Radio Bursts. [please email a.held@imperial.ac.uk for zoom link or password]