Radioactivity

[Julian]

The common reason many comic book [superheroes] have [superpowers]. A prime example would be the [Fantastic Four].

[Kai]

The emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei.

[Sarah]

the quality that some atoms have of producing a type of energy that can be very harmful to health

[Raeanne Dimick]

the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay