Victor Stein's Tumor
Jonah used the serum on Victor Stein when he fainted due to his brain tumor during the PRIDE gala in the Wizard Headquarters. Once Victor was transported in a quiet room, Jonah and Dale Yorkes injected Victor with the serum, which significantly improved both his condition and his personality, curing his brain tumor and making him much more sympathetic that he had ever been, much to his wife Janet's and his son Chase's surprise.
However, the euphoric effects of the serum eventually wore off and Victor returned to his harsh and unforgiving personality to the point he attacked his son Chase with the Fistigons, forcing Janet to mortally shoot him. When the PRIDE members and Jonah arrived to deal with the situation, Janet blamed Jonah and his serum.
Yorkes Lab Tests
Actually, Dale Yorkes had kept the vial of Jonah's serum since the PRIDE gala. He and his wife Stacey Yorkes took it back to their lab, where they ran a series of tests to determine both its nature and its capabilities. They notably discovered that the DNA of Jonah contained in the serum had the capability of triggering healing process at the molecular level, which explained how Victor Stein had healed from his tumor.
During the tests, Dale inadvertently dropped some of the serum onto his arm. The serum penetrated through the skin and quickly caused Dale to become incredibly euphoric. However, these effects also vanished as they did with Stein, causing Dale to feel immensely tired and sleepy.
When Jonah gathered the PRIDE to tell them that the Runaways were aware of their criminal activities, he confronted the Yorkeses about keeping the serum in their lab. Although Dale denied having conducted tests on it, Stacey defiantly told Jonah that they did.
The Yorkeses reexamined the serum in the light of their discovery of a ancient living being under the PRIDE Construction Site which Jonah was seemingly trying to reach. Indeed, they hypothesized that by figuring out the precise mechanisms of the serum based on Jonah's DNA, they could devise a way to kill him.
Based on Jonah's DNA, the serum displays incredibly advanced regenerative capabilities. A single dose of the serum was able to cure Victor Stein from his brain tumor, which was considered untreatable through conventional means. Jonah's DNA in the serum causes healing process at a molecular level thanks to DNA stretching.
A side effect of the serum was the great euphoria it caused when injected in a subject. As a result, Stein became much more friendly towards his family for a time. Likewise, when accidentally exposed to a drop of the serum, Dale Yorkes displayed hyperactivity and euphoria, making him enthusiastic at the idea of further exploring the capabilities of the serum, claiming it was the key to immortality.
Despite Jonah using a syringe to inject Stein with the serum, it could also directly penetrate through the skin as it did with Yorkes.
In chronological order: