Fast Blue Optical Transients (FBOTs) are a recently discovered (2014) class of transient astronomical objects. They have similarities with- but appear to be vastly more powerful.
A research team from Northwestern University, US, have recently calculated that the events appear to be able to expel a mass of 1% > 10% of the mass of the Sun at a velocity of 55% light-speed.
There is currently no explanation of how this might happen.
See: news release , Northwestern, May 2020.