Compact binary coalescences (CBC)
It's called a gravitational wave event, and it sends shockwaves through space that we can detect here on Earth. The massive dance party happens when stars and black holes are merging together!
Technical definition
A predicted astrophysical phenomenon in which two compact objects, such as neutron stars or stellar-mass black holes, orbit each other, emitting gravitational waves due to their orbital decay, ultimately leading to a merger.