This course will introduce you to the deadliest and most mysterious parts of our universe. Black holes, which warp the very fabric of space-time around them. White-dwarf stars and neutron stars, where the mind-bending laws of quantum mechanics collide with relativity. Dwarf novae, classical novae, supernovae and even hypernovae: the most violent explosions in the cosmos. We will look at what we know about these objects, and also at the many unsolved mysteries that surround them. This course is designed for people who would like to get a deeper understanding of astronomy than that offered by popular science articles and shows. You will need reasonable high-school level Maths and Physics to get the most out of this course. This is the third of four ANUx courses which together make up The Australian National University's first year astrophysics program. It follows on from a course on the Greatest Unsolved Mysteries of the Universe, and a course on exoplanets. It is not necessary to have done the previous courses first: all necessary background material is repeated here. It will be followed by a course on cosmology.