Explore the fascinating world of ultralight dark matter and its implications for cosmology in this astrophysics seminar. Delve into the mysteries surrounding dark matter's identity, production mechanisms, and interactions. Examine the concept of ultralight dark matter, including its exotic phases and vortex formation. Learn about various experimental approaches to testing these models, from large-scale universe structures to particle physics experiments. Discover composite state models like STUMP and Ultra Light Pion dark matter, and understand their model-independent observables. Investigate the connection between ultralight dark matter, early dark energy, and the Hubble tension. Gain insights into astrophysical probes, strong lensing, and diverse halo structures. Conclude with a discussion on model building, energy degeneracies, and potential solutions to challenges in the field.