Terry Sorenson's parent were both brilliant research scientist; while his mother
Margay became a celebrated success, his father
David's radical thermodynamics theries were widely dismissed. Frustrated, David began drinking heavily and beating his wife and child, who finally both moved out when Terry was seventeen. As they departed, one of David's experimental devices exploded. Terry tried to rescue his father, but an energy discharge from the smashed equipment killed David and mutated Terry into a fiery, icy super-being in a state of constant thermodynamic flux. Margay attempted to cure her son, but he gradually mutated further, becoming more powerful and mentally unstable. When Margay's experiments exhausted their savings, Terry began stealing to supply their work. Calling himself Equinox, he briefly skirmished with
Spider-Man during an attempted robbery and escaped after a subsequent battle with the
Human Torch (Johnny Storm) and
Iceman. Later, an insane Equinox attacked Spider-Man, who teamed with
Wasp,
Yellowjacket (Hank Pym), and Margay Sorenson to capture Terry, negating his powers with a thermic stabilizer they built in the
Fantastic Four's lab.
Marvel Universe 
