In addition to his appearances within the "Flash" title, the character was a founding member of the newly created Teen Titans, where he became friends with Dick Grayson, then known as Robin, later known as Nightwing. Sometime later, Wally contracted a mysterious illness that affected his entire bodily system; the more he used his speed powers, the faster his body deteriorated. This could have been caused by one of two things, Wally was a boy when the electrified chemicals altered his body, which was still developing and maturing (as opposed to Barry Allen, who was already an adult when his accident occurred) or when he was struck with a weapon during his time with the Teen Titans. As such, as Wally's body matured, his altered body chemistry was slowly killing him.