How To Grow a Black Hole is an unusual clicker game in which a trivial gravitational error is artificially transformed into a large-scale cosmic cataclysm. Instead of realistic astrophysics, the project offers a meditative process of caring for a singularity, reminiscent of a peculiar interstellar pet. The main activity boils down to absorbing light particles, which gradually increase the object's overall mass. Gradually, important scientific research is uncovered, triggering the automatic expansion of the anomaly without direct human control. The current scale of the cosmic absorber is compared to common household objects for clarity, and the results of the best achievements are broadcast on a global leaderboard.